There are two ways of controlling file types and sizes that members can upload.
The first is in Pencil Tool > Administration > Membership > Member File Storage. In this location, you can:
The second is in Pencil Tool > Manage > Manage Group > Applications > [gallery name] > Edit > File options. Please note that the permitted gallery file types for the gallery is reprinted here in orange. If you add a file type under Allowed File Extensions, only files with the extensions you type will be allowed in the gallery. If you add one or more extensions in the Restricted File Extension those files will be disallowed from the gallery.