The ToonScroll format is a manga format optimized for vertical scrolling on your smartphone.
You can select the ToonScroll format when you post on pixiv.
You can select the ToonScroll format from the desktop version of pixiv.
Currently, the mobile version and the pixiv app do not support posting in the ToonScroll format.
Check below for info on how to post. On the manga posting page, select "vertical" as the reading format, and then select the "ToonScroll" option.
When you turn this setting on, the width is fixed, and in multi-page posts, white margins between pages are hidden.
When you post a longer work in vertical format with ToonScroll on, the width of your work will be automatically adjusted for better reading on smartphones.
Left: ToonScroll OFF Right: ToonScroll ON