BUGFIX: Check if image is possible to refit on replacement

[dlubitz]

Fixes #4752

Checks if the replacement is an image and has a size.

[mhsdesign]

Im wondering if refit should rather be a noop as checking this beforehand looks kinda weird. Hmm and if we dislike this, i think the refit should throw a readable exception instead of an DivisionByNullError

[dlubitz]

The whole part is questionable, e.g. method_exists($adjustment, 'refit') should be checked by an interface. But I did't want to refactor that, I just want to get this case fixed for now.

[kitsunet]

I just want to get this case fixed for now.

Famous last words, but I get it. I think fine for the time being given the state of the thing as of now.

[mhsdesign]

oki

[mhsdesign]

there is actually quite a clever way for our method_exists($adjustment, 'refit') to get more transparent:

use @method void refit(object $image) in the interface (as its not breaking), have seen doctrine and symphony doing this

[dlubitz]

use @method void refit(object $image) in the interface
But which Interface?