I have been made aware of this, Branka, and I've checked the images in question. Both of these images were taken, without my permission, from my 500px portfolio. From your previous comments above, I'm prepared to accept that you're unsure what is copyright infringement and what isn't - so I'll overlook these particular instances.
For future reference, however, let me make the position clear:
Sharing my Google+ posts via the Google+ reshare button is acceptable, since the reshare post will contain a link back to me. Any other form of resharing is not acceptable UNLESS you (a) have my PRIOR permission AND (b) include a link back to me. If you do not adhere to this convention, I WILL report you for copyright violation.