According to this: https://w.atwiki.jp/2jiwiki/pages/471.html her name is Gigeko and it is an alternative OS-tan for Windows XP Media Center Edition.

Replaced image with larger one stored in gallery v1

Goujer said:

Replaced image with larger one stored in gallery v1

I actually uploaded it from there but I don't know why it became smaller... :/

Lily1027 said:

I actually uploaded it from there but I don't know why it became smaller... :/

The default image size on the old gallery is a scaled down version, the size you uploaded matches the default size, but you did not select the option for the image to appear at source size.