Firefox: Drag & Drop of BMP image yields "message is too long" error

Affected version


Well-known member
In Firefox, it's possible to drag & drop a BMP image onto the editor. The BMP image is rendered just fine in the editor. But when you attempt to post the message, XenForo shows a misleading error that probably isn't very helpful for the average user: "The submitted message is too long to be processed. Please shorten it."

(When you attempt to drag & drop a BMP image onto the editor in Chrome, the whole page is unloaded and replaced with the image. This isn't great either but at least it's obvious what went wrong.)