While .jpg remains universally compatible, converting production assets to modern formats drastically reduces page weight:

Online meme generators sometimes produce intermediate files with weird names. When you upload a template (e.g., a "Lilu" anime face) and apply a "randomize" effect (like random rotation or 180-degree flip), the server saves a temp file as lilu_043_random_180.jpg . The user never finished their meme, but the server cached the file forever.