MissingImageFileChecker fails with given paths

[gernotstarke]

in case images are referenced with given path (not only filename), checking those images fails.

[double16]

Is this saying something like:

<img src="/images/bg.jpg"/>

Will fail if I have $sourceDir/images/bg.jpg ?

[gernotstarke]

currently unclear, need to check... might create some testcases or specifications... (but that might take a while, I'm currently busy with other stuff, sorry)

[double16]

Fixed