Count the pixels, not the megabytes.

Check a photo’s dimensions

Most photo apps show the width and height in pixels in the file’s information or details panel. Enter them below. The calculator runs entirely in this page: it reads only the two numbers you type and never sees your photograph.

Pixels, print size, and dpi

A digital image is a grid of pixels. Its pixel dimensions, for example 1,200 × 1,800, describe how much detail it can hold. The dpi or ppi value saved with the file only says how large it would print. Adobe’s guide to image size makes the same distinction between pixel dimensions and print resolution.

In practice, a 1,200 × 1,800 file holds the same detail whether it is labeled 72 dpi or 300 dpi. For animation, ignore the label and look at the pixel count.

Choosing a scan setting

When you scan a print, the setting decides how many pixels each inch becomes. Some useful worked numbers:

• A 4 × 6 inch print at 300 dpi becomes 1,200 × 1,800 pixels, which passes the minimum.
• The same print at 600 dpi becomes 2,400 × 3,600 pixels. Before upload, our page prepares a copy at about 1,365 × 2,048, so the higher setting mostly helps if you plan to crop.
• A 2.5 × 3.5 inch wallet print needs at least 205 dpi to reach 512 pixels on its shorter side. Scanning at 300 dpi gives 750 × 1,050.
• Scanning above the detail that is actually in the print only makes a bigger file.

Why enlarging a small file does not help

If a file is under 512 pixels, it is tempting to enlarge it in an editor. That will pass our check, but the extra pixels are calculated from the ones already there. No new detail appears, and the face the animation has to follow is just as vague.

Instead, look for the original print, an earlier digital copy, or the photo as it was first sent to you, before a messaging app shrank it.

What if the file is very large?

Files over 10 MB are refused. Export a high-quality JPG copy and try that. Extra pixels beyond 2,048 on the longest side do not reach the final film, because the copy we upload is reduced to that size. They are most useful when you need to crop around one face.

Two cautions. First, a very long, narrow image, such as a panorama, can pass the 512-pixel check and still fail after that reduction: a 512 × 4,096 file becomes 256 × 2,048, which is too small. As a rule of thumb, keep the longer side no more than about four times the shorter side, cropping a copy if needed; the calculator above checks this. Second, a very large file may be slow or impossible for some phones and older browsers to open, so a smaller high-quality copy is often the more reliable choice.