Telegram developers in January 2015 recognized the advantages of WebP. (“Thanks to the WebP file format, Stickers on Telegram are displayed 5x faster compared to the other formats usually used in messaging apps”, the page at https://telegram.org/blog/stickers says.)
Fast forward to 2021. The advantages of WebP are now universally recognized. Firefox has added WebP support in 2019. Apple has added WebP support to Safari 14.0 and later versions. The Web is brimming with WebP images that have never been intended to become stickers in Telegram. That images are saved in WebP just because WebP files are significantly smaller that PNG (because of WebP's better lossless compression), because WebP files are prettier than JPEG (because of WebP's less visible artifacts of lossy compression), etc.
Telegram should recognize this new abundance of WebP files and let its users decide how they intend to send their WebP files. Please allow the following three options:
as a sticker,
as an image,
as a file.
The choice of “as an image” or “as a file” is currently controlled by the setting “compress images” for JPEG in Telegram Desktop. However, having in mind much faster generation loss of WebP (see https://youtu.be/FtSWpw7zNkI for a recent video example), Telegram should refrain from recompressing WebP to WebP unless the image exceeds certain limits (for example, “larger than a megabyte”, “larger than 1280×1280 pixels”, “bytes-to-pixels ratio larger than 1”, etc.); and that limits should be made known to the users.
Telegraph (the site, not the Graph Messenger) should also recognize the new abundance of WebP files and let its users upload WebP files or embed WebP by URL. The uploaded WebP files (like the already supported PNG uploads) should not be recompressed after upload or face worse limits than the usual 5 megabytes.