Scribus 1.5.6.1 preflight check and transparency

[pramon]

I'm a (very) new user af Scribus; I'm using it for a few days now so probably the answer to my question is obvious.

I have a document with several transparant images (transparency set with Scribus). I know PDF 1.4 supports transparency, and if I export to PDF 1.4 the transparency in the PRD looks good.
However, If I do the pre-flight check with profile PDF 1.4, Scribus returns the following errors:
- objects has transparency (for all transparent objects)
- Image dimension is smaller than its frame (for most of the image frames) No matter what I do (adjust frame to image and adjust image to frame) the error remains
How should I repeat these errors? Most important is het transparency issue

Thanks for your help!