How to join images into one: ID card front and back, before and after, collages

Many forms and verification steps ask for the front and back of an identity card as a single upload. Others just want two photos tidied into one picture: a before and after, a pair of product shots, a quick collage for a family group. Combining images is simple when the tool takes care of sizes and spacing for you.

Join two or more images

Open Join Images and add your pictures. You can add up to 20, in JPG, PNG, WebP, HEIC and other formats.
Put them in the right order with the arrows beside each picture.
Choose a layout: Side by side, Top to bottom or Grid with a chosen number of columns.
Pick how to match sizes, described below, set the space between pictures and an outer border, and choose a background colour.
Choose JPG, PNG or WebP and download.

Matching sizes

Photos taken at different times usually have different dimensions. For the joined picture to look tidy, they need a common height (side by side) or a common width (stacked or in a grid):

Match the smallest scales every picture to the smallest one’s size. Nothing is stretched, so quality is preserved. This is the default.
Match the largest scales everything up to the biggest. The smaller pictures are enlarged and may look soft.
Set a size lets you type the exact height or width for each picture, useful when a form requires a particular final size.

ID card front and back on one picture

A tidy way is to stack the two sides, with the same width:

Photograph both sides on a plain, dark or light surface, straight from above, with no glare. If needed, trim the photo with Crop & Rotate so the card fills the picture.
In Join Images choose Top to bottom and “Match the smallest”.
Use a small gap (10 to 20 px) and a white outer border so the two sides are clearly separate.
Save as JPG. If the form has a size limit, run the result through the image resizer, as explained in how to reduce an image to 50 KB.

If the form takes a PDF instead, Images to PDF can put the two photos on separate pages or you can join them first for a single page.

Protect identity documents. Share a copy of an ID only with those who truly need it, hide numbers they do not need using Blur & Redact, and mark the picture with its purpose. The guide to hiding details explains how.

Other uses

Before and after. Place two photos side by side with a clear gap. Keep both at the same height so the comparison is fair.
Product or listing photos. A grid with two columns gives a neat four-picture overview in one image.
Long screenshots. Stack several screenshots from the top of a page downwards, with no gap, to share a whole conversation as one picture.
Transparent backgrounds. Choose PNG and a transparent background if the joined image will sit on a coloured page.

Size and quality limits

The finished picture can be up to 12,000 pixels on its longest side. If your layout would be larger, the whole thing is scaled down to fit and the page tells you. A large joined image can be many megabytes, so choose JPG with a quality around 85 to 90 percent for sharing. The images are combined in your browser, so none of them are uploaded. See Are online file converters safe?.