Thread:Project:Support desk/Problem with Image thumbnailing

I use this code to insert uploaded images to wiki articles It works fine! But when I try to change its size, there is a message: error creating thumbnail /usr/bin/convert not found! And when I use different sizes the image apperas, but in some cases there is the error messages. For example when I do so: - I have error message - I have image - I have image - I have error message - I have error message - I have image And so on ... How can I fix it?