The Kanji is
http://jisho.org/kanji/details/%E8%A9%B0
but the meaning makes no sense, is it possible it's actually supposed to be
http://jisho.org/kanji/details/%E8%A9%B1

I'm pretty sure it's the first one, I just don't know how to translate it. It could be "Package" or just "Stuff" due to the amount of pictures he uploaded in the gallery.

From what I know, it can have 2 different meanings :
Mat as in, the chess term, or full. Without a context, it's a bit hard to understand what the author meant though.

Thinking about it though, this seems to be the first picture of a series of picture, so it could be representing the start of the gallery?

Nials said:
Thinking about it though, this seems to be the first picture of a series of picture, so it could be representing the start of the gallery?

This is what it means. It's short for 詰め合わせ, which means collection. Artists use it when they post a collection of sketches as one entry on Pixiv.