hello world ^^
before posting one of my drawings , I make sure on photoshop than the drawing size not exceeds 21x29.7 cm (A4).
but here the drawing take much exaggerated sizes. someone could explain me?
thank you in advance ^^

This doesn't exactly answer your question, but I'd recommend going to your settings page and changing Image resize mode to either show reduced samples or dynamically resize images. Very large images are common here as we usually prefer them over smaller ones, and this setting keeps the post page from looking like tiny text with a massive image.

Paper size and image resolution are separate things.

"A4" refers to the print size. How it is displayed on a monitor without zooming varies with the DPI.

A4 at 200 DPI is 1654 x 2339 pixels
A4 at 400 DPI is 3307 x 4677 pixels

Your images appear to mostly be A4 at 300dpi. Approximately 2480 x 3508 Pixels.

e621 does not shrink images to fit like Twitter, Tumblr, or FurAffinity.

chdgs said:
Paper size and image resolution are separate things.

"A4" refers to the print size. How it is displayed on a monitor without zooming varies with the DPI.

A4 at 200 DPI is 1654 x 2339 pixels
A4 at 400 DPI is 3307 x 4677 pixels

Your images appear to mostly be A4 at 300dpi. Approximately 2480 x 3508 Pixels.

e621 does not shrink images to fit like Twitter, Tumblr, or FurAffinity.

Ohh I understand .... thank you for your explanations chdgs ^^

Cool thanks for all you two ^^