clean up the image plugin

[dbu]

in #36 we merged the work in progress for the image plugin. it is still buggy though (see the list in #36 for what should be cleaned)

[bergie]

Some work was done in 27ee8c4

[dbu]

cool! should we create separate issues from the list in #36 to track what has been done and what is missing? it would be quite a number of issues, but would make it more visible whats missing and whats done.

[bergie]

@dbu: multiple issues sounds good. Feel free to close this one when they're in.

[dbu]

created a ton of issues here and some in create.