i bought your theme “ZA” and my portfolio show bad image. Try to solve by folow up some answer in comments and edit your source code also but it still not working. Please see in attach and help me to fix it. (http://www.bykanittha.com/portfilio/) Thank you.
I just found the solution to solved my problem.
1. Login to wordpress admin page.
2. Goto settings –> Media and then change the midium size large number than default
3. Goto plugins and add new plugins name “Regenerate Thumbnails”
4. After finish activate plugins, goto Tools –> Regen thumbnails –> Click Regenerate All Thumbnails and wait a few (depend on how many photo on your site)
5. Go to your portfolio page……. If your portfolio page still not much better, try to redo step 2 – 4.