Adv Guestbook upload photo

I have a problem with how the uploaded rezised pictures are displayed in the guestbook. The uploaded photos are displayed in a strange way. Sometimes with a brown hue/saturation, sometimes unsharp. . Hehe I am having a hard time describing it Have a look for yourself at my guestbook and see the way it is displayed. If you double click the photo's they show up correctly in full colour.

Aaaaaaaaaah please help on this topic as I have no clue where to start looking.

My website is www.clubcaribbean.nl

Allright I am editing my post because I have some additional info. It seems to be related with the CHMOD of the public folder. If I remove the write access to the public the folder the pictures will display correctly. But without the write access they won't be able to upload. Does anybody have some creative ideas?