Compress Image to 600KB — Free, Fast & Private
Two specifications in our records stop at 600 KB: the GATE photograph, at 5–600 KB, and the Japanese passport photo when you apply online from inside Japan, at up to 600 KB. They look alike and are not. GATE also caps the pixel size, and once a photo is inside that cap it has a hard time being anywhere near 600 KB — there, getting the pixels right is the real job. Japan’s in-country rule names no pixel size at all, so the 600 KB figure is the rule, and a full-resolution photo has to be compressed to meet it. This page covers both, starting with what each one actually asks for.
What fits in 600 KB — measured on this page
We dropped five real files on the compressor above and kept what it handed back. 5 of 5 came out under 600 KB.
| File | Before | After, on this page | Under 600 KB? |
|---|---|---|---|
| 12 MP phone photo | 4032 × 3024 px · 3.73 MB | 4032 × 3024 px · 550.7 KB | Yes |
| Portrait / headshot | 3264 × 4653 px · 2.25 MB | 3264 × 4653 px · 573.7 KB | Yes |
| Scanned handwritten page | 3349 × 4281 px · 2.17 MB | 3349 × 4281 px · 473.6 KB | Yes |
| Scanned signature | 2041 × 617 px · 109.1 KB | 2041 × 617 px · 102.1 KB | Yes |
| Screenshot (PNG) | 1280 × 800 px · 88.1 KB | 1280 × 800 px · 108.8 KB — larger than the original (PNG made into JPG) | Yes |
Measured 2026-10-06 in Chromium 145.0.7632.6 with this page’s own settings. The photos are public-domain and CC0 files from Wikimedia Commons; the screenshot is our own. Sizes read as the tool shows them (1 KB = 1,024 bytes); the target itself is 600,000 bytes, which is under 600 KB on either reading.
The two 600KB specifications, side by side
| Upload | File size | Pixels |
|---|---|---|
| GATE photograph | 5–600 KB | 200 × 260 to 530 × 690 px; print size 3.5 × 4.5 cm |
| Japan passport, In Japan (online application) | up to 600 KB | none stated |
| Japan passport, From abroad (embassy or consulate) | 20–2048 KB | none stated |
GATE’s own wording puts both limits in one breath: “The maximum pixel resolution is 530 x 690 pixels and the minimum resolution is 200 x 260 pixels. The file size must be minimum of 5 kB and a maximum of 600 kB.” It also sets a 5 KB floor, so a photo crushed far below the ceiling can fail too. The GATE photo tool checks the band, the pixel range and the shape together; for a passport photo, the passport photo maker handles the head framing and background that a compressor cannot.
Japan’s record carries the Ministry of Foreign Affairs’ own distinction. Inside Japan: “Applying inside Japan, MOFA accepts jpg only and 600 KB or less. It states no minimum and no pixel dimensions.” From abroad: “Applying from abroad, MOFA accepts jpg, jpeg, bmp and png and 20 KB to 2 MB. The upload is recompressed, so a file near the top of that range can still be refused after compression.” So if you are applying through an embassy or consulate, 600 KB is not your ceiling at all — the 2MB page sits just under the top of that range, and given the note’s warning about recompression, the 1MB page leaves more room.
GATE: why the pixel cap bites before the kilobyte cap
An uncompressed colour pixel is 24 bits — three bytes. So you can work out the raw, uncompressed size of an image at each pixel cap, and compare it with 600,000 bytes:
- GATE at 530 × 690: 365,700 pixels × 3 bytes = 1,097,100 bytes raw. A 600 KB file would spend 13.13 bits on every pixel.
- A 12-megapixel photo (4000 × 3000) left at full size: 12,000,000 pixels, so 600,000 bytes allows 0.40 bits per pixel.
The first line says that at GATE’s largest permitted size, 600 KB is a budget a JPEG has little reason to fill: compression exists to store an image in a small fraction of its raw size. The second line is the trap. If you upload a full-resolution phone photo, the file-size rule is the one you are fighting, and even when you win it the photo is still more than 7 times wider than GATE allows. A 600 KB file that is 4000 pixels wide passes one rule and fails the other.
Japan: where the kilobytes are the rule
With no pixel size stated for the in-country upload, the 600 KB line is the one that decides it, and the arithmetic runs the other way. A 12-megapixel photo held at full size has 0.40 bits per pixel to work with inside 600,000 bytes. Cropped to a 413 × 531 passport frame — 219,303 pixels, 657,909 bytes raw — it has 21.89, nearly the full 24 of an uncompressed pixel. Cropping to the frame first is therefore the gentler path, but it is not required by the rule: a compressed full photo under 600 KB meets the file-size line too.
Whichever you choose, the rest of the photo rules still apply, and they are about the picture, not the file: Plain white or light-coloured background with no shadow. Head 32–36 mm from chin to crown. Taken within last 6 months. Neutral expression with mouth closed. No compression setting changes any of those.
Two honest routes to a 600KB file
Route one: fix the pixels, then compress. Crop to the required framing and, where the form sets one, resize into its pixel range — the crop tool and the passport-size resizer both do this — and then drop the result here. By the arithmetic above, a photo at those pixel sizes has a large budget per pixel inside 600 KB, and you have chosen the framing rather than leaving it to software.
Route two: compress the full photo here. If a portal only limits the file size, or you just need a 600 KB copy of a photograph, drop it straight in. The compressor lowers JPEG quality first, at the photo’s full pixel size. Only if its lowest quality still misses 600,000 bytes does it reduce the pixel dimensions, and when it does, it says so and shows you the new size. It will not shrink the photo to a form’s pixel range on its own — that is route one.
Print size, DPI and the passport frame
Both photographs are passport-sized prints underneath. The frame MiniPx builds for a Japanese passport photo is 35×45 mm, which is 413×531 pixels at 300 DPI — a print size turned into pixels, not a figure MOFA sets for the upload. GATE gives a 3.5 × 4.5 cm print size and a 530-pixel maximum width, which works out to 530 ÷ (3.5 ÷ 2.54) ≈ 385 pixels per inch across that width. A DPI field stored in a file changes none of this: it is a label for printing, not extra pixels. If a form asks about it, the DPI checker shows what your file states.
One unit note. This page aims under 600,000 bytes, counting 1 KB as 1,000 bytes. A validator that counts 1,024 bytes to the kilobyte would allow 614,400 bytes for the same number, so a file under 600,000 passes either way.
Everything runs in your browser. Your photograph is not uploaded anywhere while it is compressed.