well this is what we can conflicting information and I was more looking for more accurate information then what you posted. The error is telling me and you that we can not access that file and then your telling me the image is fine. Well both can not be true.
Is the image 666 or 644 permissions? Have you tried setting permissions to 666 or 777 if it goes exist.
Basically getimagesize can not access the image.
Your own site shows you have permissions issues and or missing images For Sale - Team Buick Classifieds
Your data directory must be 777 permissions recursively. I was looking for more direct information to be able to make a more detailed analysis and finally had to go behind the scenes and look at a url since you where not giving info. 1960 - 1969 - Team Buick Classifieds
There is alot of ads try running this query in phpmyadmin to find out specifically what ad there is thats an issue. The reason i am saying is you have alot of data corruption there.
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