Ask to convert image to JPG

[UnitedMarsupials]

The "Image" entry under the "Insert" menu is disabled (greyed-out) for all my WhatsApp chats. An image can be sent as a file -- by going into the top "Chat"-menu, and picking the "Send File" option, but that's treated differently on the receiving end.

[hoehermann]

Thank you for the question. :)

WhatsApp does not support rich text messages in the way Pidgin does. A more detailed explanation is here. TL;DR: It is possible, but not without caveats.

Sending an image as a file should work, though. How is it treated differently on the receiving end? Is the receiver the official app on Android or iOS?

[UnitedMarsupials]

WhatsApp does not support rich text messages in the way Pidgin does

Uhm, I was not talking about rich text here (though simple stuff like "italic" and "bold" should be possible). :)

I was talking about embedding images...

How is it treated differently on the receiving end? Is the receiver the official app on Android or iOS?

The official WhatsApp on iOS is showing an image sent as a file as an attachment -- the image itself is not shown, until you tap on it, see screenshot below:

[hoehermann]

Thank you for the clarification. I understand the issue better now.

As far as I know, WhatsApp does not actually support displaying PNG. Only JPEG (and WebP for stickers). When I try to send a PNG with the official client, the image is implicitly converted to JPG (losing quality and alpha channel). If you explicitly convert to JPG first (with GIMP, graphicsmagick, or something similar) and then use the "Send File" menu – the JPG should be displayed on the receiver as expected. Choosing a sampling factor for chroma downsampling of "4:2:0" might be necessary for iOS clients cooperate (I am not sure about that).

[UnitedMarsupials]

the JPG should be displayed on the receiver as expected

Yes, indeed... It never occurred to me to test with another file-type... But, if it that works, why can't the same functionality be made available through the "Insert" menu?

[hoehermann]

if it that works, why can't the same functionality be made available through the "Insert" menu?

Good question! 👍 Unfortunately, the answer is rather involved. 😕 As far as I know, the "insert" menu uses the same mechanics as image-pasting. For more details about that, see #210.

What do you think of WhatsApp's implicit png-to-jpg conversion? Automatic conversion could be convenient, but to me it feels like loss of control. I could ask the user "this is a non-jpg image file, do you want it converted to jpeg or sent as a document message? yes/no/cancel". I currently do not feel motivated to implement that, but it could be a thing for the future.