Why do photos from the WhatsApp group arrive so grainy?

What exactly does WhatsApp do to your photo?

Two things at once, and the second is the nastier one. First the photo is shrunk: the pixel count drops until the longest side lands somewhere around 1600. Then it is saved again as a JPEG at a lower quality, which means detail is thrown away that does not come back. Shrinking is a choice, discarded detail is final.

A Dutch photographer measured it with a photo from a system camera. Original: 6000 by 4000 pixels, 21.8 megabytes. After one pass through WhatsApp: 1600 by 1066 pixels, 660 kilobytes. Of the 24 million pixels, 1.7 million are left, and of the file about three per cent. You can look at his comparison side by side.

Exactly how much falls away depends on your phone, your settings and the version of the app. In an older comparison by Androidworld, photos out of WhatsApp came out at 2048 by 1536 pixels, while Signal left the original size alone. The direction is always the same and it only ever goes one way.

Why do they do it? Because that file has to be at the other end in two seconds, including on one bar of signal in a venue where eighty people are on the same network. For a message to your mother that is a fine trade. For the photos of your wedding it is not, and that is the only thing wrong with using WhatsApp: it is the wrong tool, not a wrong decision.

How big can you still print 1600 by 1066 pixels?

Here comes the sum nobody puts next to it. A photo print is made at 300 pixels per inch. Divide 1600 by 300 and you get 5.3 inches, or 13.5 centimetres. In height: 1066 divided by 300 is 3.6 inches, so 9 centimetres.

Thirteen by nine centimetres. That is just under a normal print of 10 by 15, and that is the limit right there. Up to that size a photo from the group chat looks perfectly good. Stretch it to A5 and you are at about 190 pixels per inch, which passes at arm's length. Go to A4 or to a canvas above the sofa and you are around 140: hair becomes a smudge and you can see blocks in a plain sky.

For a photo book this is the point where it hurts. A page of a standard photo book is wider than thirteen centimetres, so every photo you want to print across the page drops out. Photos that arrive as originals can go across the page, and you can crop or straighten them as well without anything falling apart.

Does that HD button not help then?

Partly, and it is an honest improvement. Since 2023 there is a button when you send that lets you pick HD instead of standard. WhatsApp itself warns that the file can then become up to six times larger. But it is not an original: it is still compressed, just less.

There are two practical catches. The button is not on by default, and you have to tap it per photo unless you fix it in the settings under media upload quality. Fixing it only applies to your own phone and not to your guests'.

And that is the heart of it. Any solution that asks your guests for an extra action at the moment they are paying the least attention does not happen. Somebody forwarding twelve photos at half past one is not going into a settings menu. That is not laziness, that is a party.

Does sending it as a document work?

Yes, and that is the honest solution. Send a photo not as a photo but as a document and WhatsApp leaves the file alone. You get exactly what was taken: every pixel and all the colour information. For one important photo to one person this is simply the right way to do it.

Only: try explaining that to eighty guests at eleven at night. On an iPhone it runs through the Files app instead of through your camera roll. On Android you tap the paperclip, choose Document and go through your file manager. Those are three extra steps for somebody with a glass in their other hand.

And then they arrive as a row of file names in a chat, not as an album. With ten photos that is doable. With twelve hundred photos from forty guests you scroll for two evenings to save it all, and you still do not know who sent what. So it does not scale for a party, which is why people collect those photos another way.

And video? That takes it even harder

Video gets hit hardest of all. In a test on an iPhone, a video at standard quality arrived at 848 by 476 pixels. That is less than the DVDs of old, while that same phone films in Full HD or 4K. With HD mode on it becomes 1280 by 718, still under Full HD.

You notice it the moment you put a clip like that on a television. The speech somebody filmed for you is bearable on a phone and a block puzzle on a 55 inch screen. The sound survives reasonably well, so you still hear what is said. You just no longer see the face that goes with it.

With video this counts for more than with photos, because you usually only have one. Twelve photos were taken of the cake. Of your brother's speech there is one recording, and it is on the phone of somebody who then sent it through the group chat. That is exactly the reason to have that one recording arrive somewhere else.