How to Put Two Photos Side by Side
Four steps and you are done. No account, no waiting for a server response, no watermark stamped on your output.
- Upload Photo 1. Click the left upload zone or drag a file onto it. This becomes the left photo (or top photo in Vertical mode). JPEG, PNG and WebP all work.
- Upload Photo 2. Same process on the right zone. This becomes the right (or bottom) photo. You can swap them later with the Change button on each slot.
- Adjust the settings. Choose direction (Side by Side, Vertical, Diagonal or Diagonal Square), width mode, border size, corner radius and background color. Toggle the divider line or labels on if you need them. The preview updates live as you change anything.
- Download. Click the Download button. The file is named
side-by-side-photo-collagephotoapp.jpg(or .png or .webp, depending on your format choice) and saves directly to your device.
That preview is not decorative. It is rendered at the best quality and generates the download. What you see is exactly what you get in the photo.
Proportional vs Equal Width: Which Should You Use
This is the setting most tools either bury in advanced options or skip entirely. It matters a lot depending on what you are making.
Proportional Mode
Both photos are normalized to the same height. Each keeps its original width-to-height ratio. The result is that a portrait photo (tall and narrow) and a landscape photo (short and wide) placed side by side will appear at very different widths. The canvas height is fixed but the widths vary.
Use this when you want to preserve the full composition of each photo without any cropping. A travel photographer placing a wide canyon shot next to a portrait of a local would use proportional mode so neither image is trimmed.
Equal Width Mode
Both photos are forced into identical cells. If the photos have different aspect ratios, the tool crops each to fill its cell from the center outward. The output looks like a matched comparison grid where both panels are exactly the same size.
Use this for before-and-after comparisons where visual symmetry matters. A skincare brand posting a treatment result, a personal trainer documenting a client transformation or a dentist showing a whitening result, these all need both images to sit in equal frames so the viewer registers the change rather than the size difference.
Diagonal and Diagonal Square Layouts
The Diagonal layout splits the canvas along a diagonal line. Photo 1 fills one triangular half and Photo 2 fills the other. Two directions are available: Left Up (where Photo 1 occupies the upper-left triangle and Photo 2 occupies the lower-right triangle) and Left Down (where Photo 1 occupies the lower-left triangle and Photo 2 occupies the upper-right triangle). A divider line option draws the diagonal boundary between the photos.
Diagonal Square is a variation where both photos are placed as squares in diagonally opposite corners of the canvas. The background color fills the other two quadrants. This gives a clean grid-within-a-square look that works particularly well for product comparisons and social media content where a bold asymmetric layout stands out in a feed.
Corner Radius applies to both layouts. It rounds the outer corners of each photo cell. Combined with a visible background color in the empty quadrants, the Diagonal Square layout with corner radius produces a polished card-style composition. Set corner radius to 0 for sharp edges on all four corners.
Border and Corner Radius
The Border slider adds equal padding on all four sides of the canvas. At 0px the photos fill the full canvas with no breathing room. Increase the border when you want the photos to sit inside a colored frame rather than touching the edges. The background color fills the border area, so a white border with a dark background or a black border with light photos gives a clean framed effect.
Corner Radius rounds the corners of each photo independently. It scales with the image so a value of 40px at Original size still looks proportionate whether the output is 800 pixels wide or 4000 pixels wide. Set corner radius to 0 to keep sharp square corners on all photos.
Labels and Dividers: Making Your Comparison Impossible to Misread
A side by side photo without labels is a comparison that requires the viewer to already know which side is which. Labels eliminate the ambiguity. A divider line sharpens the boundary between the two photos so the eye knows exactly where one ends and the other begins.
Using Labels Effectively
Toggle Labels on and you get two independent text fields, one for each photo. Each label has four position options: top-left, top-right, bottom-left and bottom-right. You can set them to different positions on each photo.
The classic setup is Before in the bottom-left of Photo 1 and After in the bottom-right of Photo 2. But the position options exist because not every photo works that way. A skincare before photo where the skin texture is most visible in the upper-right corner benefits from the label placed out of the way at bottom-left. A product photo where the packaging detail is at the bottom needs the label at top-left so it does not cover anything important.
Three size options (Small, Medium, Large) map to percentages of the photo height rather than fixed pixel values. This means the label scales correctly whether your photos are 800 pixels tall or 4000 pixels tall. The background opacity slider controls how strongly the dark rectangle behind the text blocks the photo underneath. At 60 percent (the default) the label is legible without completely obscuring the photo. At 0 percent the text floats with no background at all, which works well on simple solid-color backgrounds but gets lost on busy images.
Using the Divider Line
The divider is drawn at the boundary between the two photos. Thickness ranges from 1 to 80px on the full-resolution canvas. For a subtle hairline, 1 to 3px works well. For a bold graphic split bar, push it to 20px or beyond. On Diagonal and Diagonal Square layouts the divider follows the diagonal line rather than a straight horizontal or vertical edge.
Side by Side Photo Sizes for Every Platform
Uploading at the wrong dimensions does not just look bad. Some platforms actively crop or compress images that do not match their expected ratios. Here is exactly what each preset does and when to use it.
Instagram Feed Posts
The Instagram Post preset outputs at 1080×1080 pixels, the standard square format that Instagram displays in the feed without cropping. For side by side comparisons, square output means each photo gets roughly 540 pixels of horizontal space. That is plenty for facial or product detail at normal viewing sizes. Instagram compresses all feed images to 1080px wide regardless of what you upload, so uploading larger than 1080px just adds file size without any quality benefit.
Instagram Stories and Reels
The Instagram Story preset outputs at 1080×1920 pixels, which is the full-screen 9:16 format. In Vertical mode, this preset gives both photos 1080×960 pixels of vertical space each, filling the entire Story screen with a clean top-and-bottom comparison. Renovation accounts, fitness coaches and beauty creators use this format constantly because the full-screen before-and-after is one of the highest-engagement Story formats on the platform.
Twitter/X
The Twitter/X preset outputs at 1600×900 pixels. This 16:9 landscape ratio displays inline in the timeline without being cropped. Side by side comparisons at 1600×900 give each photo 800 pixels of width, which is enough to clearly see the difference between two product variants or two versions of a photo edit. The wider format also means the viewer does not need to tap to expand the image to understand the comparison.
The Facebook preset outputs at 1200×630 pixels, matching the recommended Open Graph image dimensions. At this 1.91:1 ratio, horizontal side by side photos sit naturally without any cropping or letterboxing from Facebook. Vertical photos at this ratio will have background color bars on the left and right edges.
Original Size for Print and High Quality
Original size uses the full resolution of your photos with no scaling. If you upload two 12-megapixel phone photos at 4032×3024 pixels each, the output at Original size will be roughly 8000 pixels wide (two widths plus the gap). That resolution is more than adequate for A4 or letter-size print at 300 DPI.
One practical note on print: screen images are typically captured at 72 DPI. Print services usually require 300 DPI. The DPI setting only matters when you are printing. The total pixel count determines the maximum print size at 300 DPI. A 6000×3000 pixel merged image prints at 20×10 inches at 300 DPI. If your print service has specific requirements, export as PNG at Original size for a lossless file and check with your provider.
What People Actually Use Side by Side Photos For
The format is simple. The reasons people reach for it are more varied than most tool pages acknowledge.
Before and After Documentation
The most common use case by a significant margin, and for good reason. A before-and-after side by side communicates transformation without requiring the viewer to read anything or remember what they saw a moment ago. Both images are in the same frame. The difference is immediately visible.
Home renovation contractors post before-and-afters of kitchens, bathrooms and garden transformations to attract new clients. Personal trainers post client body composition changes. Skincare and makeup brands post treatment results. Orthodontists post smile transformations. Landscapers post garden makeovers. In every case the format does something a verbal description cannot: it shows evidence rather than asserting it.
Product Variant Comparisons
E-commerce sellers need to show color options, size variants and packaging versions without forcing customers to scroll through a product carousel that many users never bother with. Placing two colorways of a sneaker side by side in a single image turns a browsing interaction into an instant visual decision. The same logic applies to fabric swatches, paint colors, phone case designs and food packaging. The viewer compares without clicking.
Fashion and Style
Two outfits side by side for a styling decision. A new purchase next to what was already in the wardrobe. An outfit in two different color palettes. Fashion content creators and personal stylists use side by side photos to give their audience something to react to rather than just something to look at. Comments on "left or right?" posts tend to be much higher than on single-outfit posts.
Progress and Milestone Documentation
Fitness progress over three months. A child in the same outfit at age 2 and age 5. A handmade quilt at the halfway point and at completion. These are moments worth documenting properly, not just screenshot-and-share. A properly made side by side photo with consistent framing and a clean background is something people actually print, frame and keep.
Real Estate and Interior Design
Before-and-after staging photos. Two layout options for the same room. The view from the same window in summer and in winter. Real estate agents and interior designers use comparison photos in listings, pitches and social content because the before-and-after format tells the story of transformation more compellingly than any individual photo can.
Creative and Editorial Work
A photographer placing two shots from the same session to show how different light direction changes the mood entirely. A graphic designer comparing two versions of a logo. A food stylist showing raw ingredients next to the finished dish. In editorial and creative work, the side by side format is a communication tool between the creator and their client or audience, a shared reference frame that keeps everyone looking at the same thing.
JPEG, PNG or WebP for Side by Side Photos
The format choice matters more than most people realize, especially when the output is going somewhere specific.
JPEG is the right choice for photographs, skin tones, natural landscapes and any image where subtle color gradients matter. It produces smaller files than PNG at equivalent visual quality. The tradeoff is lossy compression, which introduces visible artifacts at high-contrast edges. This tool defaults to 100% JPEG quality so you get maximum-quality output. Lower the slider only if file size is a specific constraint.
PNG is lossless. No detail is discarded. The file is larger but the pixel data is preserved exactly. Use PNG when your photos contain text overlays, logos or flat-color graphics, when one of your source photos was a PNG with transparency or when you want to keep the full transparent background option from this tool.
WebP delivers smaller files than both JPEG and PNG at equivalent visual quality. As of 2026, WebP is natively supported in Chrome, Edge, Firefox and Safari. Use it when web performance matters and your audience is on modern browsers. Avoid it for content going into email campaigns or being shared to platforms that still have inconsistent WebP support.
Your Photos Stay on Your Device
This is worth saying directly because most online photo tools do not work this way.
Every operation in this tool runs entirely here itself. When you upload a photo, it is read into browser memory as an object URL. When you click download, the canvas renders the combined image and saves it directly to your device. Nothing is sent over the network. Nothing is stored on a server. Nothing is logged.
This matters for photos that have personal significance, photos of clients, photos from professional shoots and photos you simply do not want passing through a third-party server. You have complete privacy by default, not as an opt-in feature.
More Ways to Work with Your Photos
Side by side merging is one specific tool for one specific format. For everything else:
- Multiple photos in one image: The Merge Images tool handles horizontal, vertical and grid layouts for two or more photos at once, with fit mode controls and full social media presets.
- Instagram profile panoramics: The Instagram Grid Maker splits a single wide image into correctly numbered tiles for posting as a panoramic grid on your Instagram profile.
- Creative collages with templates: CollagePhotoApp on iOS and Android gives you a full collage editor with overlapping layouts, stickers, frames and text. It is free to download.
Ready to make stunning collages?
Download CollagePhotoAppFrequently Asked Questions
Does this tool upload my photos to a server?
No. Every operation runs entirely here itself. Your photos never leave your device and are never sent to any server, regardless of how large the files are.
What is the difference between proportional and equal width mode?
Proportional mode keeps each photo at its original aspect ratio, normalizing both to the same height. A portrait and a landscape photo will appear at different widths. Equal width mode forces both photos into identical cell dimensions with center cropping, so the output looks like a symmetrical matched comparison regardless of the original photo shapes.
Can I add text labels like Before and After?
Yes. Toggle Labels on, type the text for each photo and choose one of four corner positions. You control the label size, text color and the background opacity behind the text. Labels are baked into the downloaded image, not added as an overlay layer.
How do I add a divider line between the two photos?
Toggle Divider Line on. Set the thickness (1 to 80 pixels) and pick a color. The divider is drawn at the boundary between the two photos. On Diagonal and Diagonal Square layouts it follows the diagonal split line.
Will this reduce my photo quality?
Not with default settings. JPEG quality defaults to 100% and output defaults to Original size. Quality loss only happens if you deliberately lower the JPEG quality slider or choose a size preset smaller than your source photos.
What formats can I upload and download?
Upload: JPEG, PNG and WebP. Download: JPEG, PNG or WebP. PNG is the only format that supports transparent backgrounds. WebP gives the smallest file size for modern browser use.
How do I use this on iPhone or Android?
Open this page in your mobile browser. Tap each upload zone to select a photo from your camera roll, adjust the settings and tap Download. No app install needed. This tool also works excellently in mobile browsers on both iOS and Android.
What size should I use for Instagram?
For a square feed post, use Instagram Post (1080×1080). Instagram compresses all feed images to 1080px wide so this preset matches exactly. For a full-screen Story or Reel cover in Vertical mode, use Instagram Story (1080×1920).
Can I stack the photos vertically instead?
Yes. Switch the Direction to Vertical. Photo 1 goes on top and Photo 2 goes below. For a creative split, the Diagonal and Diagonal Square options divide the canvas along a diagonal line instead of a straight horizontal or vertical edge.
What is the difference between a side by side photo and a collage?
A side by side photo places exactly two images in a clean comparison layout, optimized for clarity. A collage typically involves multiple images, creative layouts, overlapping frames, stickers and text. For full collage creation with templates on your phone, CollagePhotoApp handles that workflow.
Can I put two photos side by side without downloading any app?
Yes, which is the whole point of this tool. It runs entirely in your browser. No app download, no account, no extension. Open the page, upload two photos and download the result in under a minute.