Social Media Resizer
One upload, every crop you need
Pick the platforms, get correctly sized centre-cropped images for each, exported together as one archive.
Social Media Resizer
Runs in your browser · nothing uploaded01 — How to use Social Media Resizer
02 — Getting good results
03 — Questions
No. Every crop is rendered in your browser, in a background worker, and packed into a ZIP locally. Nothing is transmitted — which matters more than usual here, since the source is often an unpublished photograph.
Because that preset is larger than your source in at least one dimension, so the image had to be enlarged to fill it. The queue row says so, with the factor involved. The fix is a higher-resolution original; no tool can recover detail that was never captured.
Not here — crops are taken from the centre, which is the right default for most compositions and keeps the tool a one-click operation. For deliberate framing, crop the image first with the Image Crop tool and then run the result through this one.
Outputs are flattened onto white, because the lossy formats these slots expect cannot store transparency and platforms composite onto their own backgrounds unpredictably. Choosing PNG preserves the alpha channel if you need it.
04 — More about Social Media Resizer
Why one source and many outputs
Every platform publishes its own dimensions, and the list changes often enough that keeping up manually is tedious. The practical problem is not knowing the numbers — those are published — but doing eighteen separate crop-and-export operations without mistakes. This tool inverts that: one good source in, a named set out, with the arithmetic done consistently. The naming matters as much as the resizing, because a folder of files called image-1 through image-18 is only marginally more useful than doing it by hand.
Cover fit, and what it trades away
There are two reasonable ways to fit an image into a differently shaped box. Contain scales until the whole image is visible, leaving empty bars on one axis. Cover scales until the box is full, trimming whatever overflows. This tool uses cover, because platform slots composite onto their own backgrounds and letterbox bars read as a mistake rather than a choice — and because several slots crop again on their own terms, which turns bars into unpredictable margins. The cost is that content near an edge can be lost, which is why the queue shows every output before you download them.
Resolution is the constraint that matters
The single factor that determines whether this tool produces good results is the resolution of what you feed it. Downscaling is well-behaved: many source pixels average into each output pixel, and the result is faithful. Upscaling is not, because the information simply is not there. A 1000px-wide source asked to fill a 2560px banner is enlarged by more than two and a half times, and no amount of resampling sophistication changes the fact that most of those pixels are interpolated guesses. The tool flags this per output rather than failing, because a soft image is sometimes acceptable and the judgement is yours — but it should be a judgement, not a surprise.
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Same shell, same shortcuts, same promise: nothing leaves your browser.