In short: Telegram wants stickers on an exact 512×512 canvas with one side filling the full 512px, and a genuinely transparent background — as a static PNG, or as a short WebM for a video sticker. @Stickers will bounce anything that doesn't match. RemoveGifBG's Telegram preset (512×512) and PNG/WebM export get both right before you submit.
You're building a sticker pack to submit through Telegram's @Stickers bot — maybe from a looping GIF, a clip from a video, or original art. Telegram checks the canvas size and transparency of every file you send it, and it's easy to submit something that looks right in a preview but gets rejected: wrong dimensions, a background that isn't real alpha, or a video sticker that isn't actually in the format @Stickers expects.
RemoveGifBG has a Telegram Sticker preset (512×512) in the output-dimensions dropdown, so the canvas is correct before you export — no separate resize pass. Output formats include transparent PNG for static stickers and WebM for video stickers, so you can go straight from source GIF/video to a file @Stickers will accept.
Run your source clip through once, pick the Telegram preset and the output format that matches whether you're submitting a static or video sticker, and download a file sized and formatted for direct submission.
What Telegram's sticker submission expects
Make a Telegram Sticker — Free
See also: WeChat sticker guide · LINE sticker guide