The quick answer: pick the size, then compress
The form says maximum 200 KB, the photo is 4 MB, and the upload button keeps saying no. Open Compress Image to 200 KB. The limit is already selected, so there are only a few clicks left.
- Choose your photo, or drop it on the page. Several photos work too, and the limit applies to each one.
- Press Compress. The list shows the new size of each file, and its size in pixels if it had to be made smaller.
- Open the compare view and look at faces, text and edges at 100 percent.
- Download the file and upload it where it was needed.
Another limit? There are matching pages for 100 KB and 50 KB, and Reduce Image Size takes any number from 5 to 50,000 KB. One detail forms rarely mention: the tool counts a kilobyte as 1,000 bytes, so the file is under the limit however the form counts. Nothing is uploaded; the photo is compressed in your browser.
KB versus MB: why 4 MB is not close
On most forms, and on a Mac, 1 MB is 1,000 KB. A 4 MB photo is therefore 4,000 KB, and a 200 KB limit asks for a file 20 times smaller (4,000 divided by 200). Phone photos are often 3 to 10 MB because cameras save at a very high quality with a lot of invisible detail, so this is a normal request, not a hard one.
Some systems count in units of 1,024 instead, which makes the same file look slightly smaller. That is why the tool counts the smaller way: a file under 200,000 bytes passes either count.
Two levers: quality and pixels, and the order to pull them
A file gets smaller in only two ways. You can save the pixels more cleverly (lower the quality), or you can keep fewer pixels (lower the dimensions). Halving both sides leaves a quarter of the pixels, so dimensions are a strong lever. Quality is the gentle one, and the cheapest to give up first.
The size-target pages pull them in the right order for you. They lower the quality first, down to a floor where pictures start to look rough, and only then shrink the pixels, by just enough. In the tool's own tests, a 3,072 by 2,048 pixel photo of 3.0 MB came out at about 1,500 by 1,000 pixels, just under 200,000 bytes, at a quality in the 60s, and a calmer 2,048 by 1,536 photo kept about 1,580 pixels across at a similar quality. Detail decides the outcome: foliage costs bytes, smooth water and sky give them back.
If you work by hand, use the same order:
- Crop away what you do not need. Fewer pixels of empty wall means more bytes for the subject.
- Set the size in pixels if the form gives one, using Resize Image, before you compress.
- Compress to the size limit last, starting from the original and never from a copy that was already compressed.
JPG or PNG: photos versus screenshots
For a photo, choose JPG. A photo saved as PNG is many times larger than the same photo as JPG, and almost every form accepts JPG. If your file is a HEIC from an iPhone, the compressor opens it and saves a JPG; see open HEIC photos on Windows for the details.
For a screenshot, a logo or a stamp with flat colors, PNG can win. In the tool's tests, a text screenshot of 104 KB came down to 19 KB at full size by using only 8 colors, and the text stayed readable. A photo cannot do that: as a PNG it normally keeps at least 96 colors and gives up pixels instead. WebP and AVIF go smaller still, but many forms reject them, so use them only where you know they are accepted. JPG vs PNG vs WebP vs AVIF covers the choice in full.
Rough pixel sizes for each limit
These widths come from the tool's tests on two ordinary photos. They are rough: a photo with fine texture lands lower, and a smooth one or a plain background lands higher. A signature scan on white paper is the easy case, at about 8.6 KB from a 96 KB start in one test, with no pixels lost.
| Limit | Typical longest side of the result | Fine for |
|---|---|---|
| 50 KB | About 735 to 785 pixels | Passport style photos, small profile pictures |
| 100 KB | About 1,070 to 1,150 pixels | Profile photos, listings, content pictures on a page |
| 200 KB | About 1,500 to 1,580 pixels | Clean on a screen; product shots and blog images |
| 500 KB | About 2,000 to 2,600 pixels | Email attachments and larger web pictures |
At a smaller limit the picture is shown smaller too, so a result 750 pixels wide looks soft if a form stretches it to fill a wide box. The result row always shows the final pixel size next to the file name, so you can judge it before you upload.
Do not over-compress an official photo
Passport, visa, exam and ID forms usually set more than a size in kilobytes. They may also fix the file type, the pixel dimensions or proportions, and the background color. The compressor aims only at the kilobytes, and it may make the picture smaller in pixels to get there, so check the other rules on the result.
A form that sets a minimum as well as a maximum, such as 10 to 20 KB, is a special case. The tool stays at or under the limit, and a very simple picture can come out well below it. It does not aim for a minimum size, so if the result is too small, start again from a larger original.
What goes wrong, and the fix
- The result is still over the limit. A picture that cannot reach the limit without becoming tiny is returned at the smallest useful size, and a note says the limit was missed. Crop it, or choose a larger limit.
- The photo looks soft. There are too few pixels for how big the form shows it. Crop to the part that matters and compress again from the original.
- The file came back unchanged. It was already under the limit and as compact as it can be. Nothing was lost, so use it as it is.
- The form still says no. The size is probably not the only rule. Look for a pixel size, a file type or a total for several files, and divide the limit by the number of files if it is a total.
What to do next
If the form wants a PDF, save a picture as a PDF and then see how to compress a PDF. If you are preparing pictures for your own site, the budgets are different: read compress images for your website. And before you send a photo to a stranger, remove its location data. The compressor strips camera details, date and GPS location by default.