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Photos sent as images on WhatsApp are capped at 16MB and are resized so the longest edge is around 1600 pixels (higher with HD mode), then re-compressed as JPEG. Sending a photo already sized to about 1920 pixels and 1MB gives WhatsApp almost nothing to strip, which is why pre-compressed photos arrive sharper than originals.
The first is the file size cap: 16MB for anything sent as media. Almost no single photo reaches this, so it rarely bites — it is really a video limit that happens to apply to images too.
The second is the one that matters: WhatsApp resizes and re-compresses every photo sent through the picker. The longest edge is scaled to roughly 1600 pixels in standard mode, and the result is saved as a JPEG at a moderate quality setting. A 4000 by 3000 pixel original becomes about 1600 by 1200 and a few hundred kilobytes. That resize is where the visible loss comes from.
Newer versions offer an HD toggle in the photo editor. It raises the resolution ceiling substantially — long edges of several thousand pixels — and uses a gentler quality setting. It is a real improvement, but it is still a resize and a re-compress, it has to be selected for each photo, and it produces a much larger file for the recipient to download.
Because WhatsApp scales its processing to what it receives, the sharpest results come from handing it a photo that is already close to its target. In practice that means a longest edge of around 1920 pixels and a file size of around 1MB, saved as a high-quality JPEG.
At those dimensions WhatsApp performs at most a small resize — 1920 down to 1600 is a gentle step — and the re-compression has little detail left to destroy. The photo arrives looking almost exactly as you sent it. Hand it a 12-megapixel, 6MB original instead, and the aggressive scale-down plus re-compression is what produces the soft, blocky result people complain about.
These suffer worst from WhatsApp’s compression, because JPEG artifacts cluster around sharp edges — exactly what text is made of. A screenshot of a receipt or a photographed page of notes can become genuinely hard to read.
Pre-compressing helps more here than anywhere. Keep the longest edge at the full 1920 pixels so the text stays large, and let the compressor handle the file size. For a document that needs to be readable in full, send it as a document rather than an image, or use a PDF.
The image compressor here is configured for exactly this sweet spot: it resizes to a 1920-pixel longest edge and targets roughly 1MB, using a high JPEG quality setting. It handles a whole batch at once and runs in your browser, so the photos are never uploaded.
Resize photos to the sweet spot
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Open the toolPhotos sent as media are capped at 16MB, but the more relevant limit is the resize: WhatsApp scales the longest edge to around 1600 pixels in standard mode and re-compresses as JPEG.
Standard mode targets a longest edge of roughly 1600 pixels. HD mode allows considerably more. Both re-compress the image as a JPEG.
A longest edge of about 1920 pixels at about 1MB, saved as a high-quality JPEG. That is close enough to WhatsApp’s target that its own processing removes very little.
Because WhatsApp compresses harder the bigger the input. A photo already near its target size needs only a gentle resize, while a large original gets an aggressive scale-down and re-compression.
No. Documents are transferred unchanged. The trade-off is that they do not display inline in the chat.