Why does my laptop only upload a handful of photos from my blackberry smartphone?

I have 200 photos on my blackberry and I am trying to free up space on my handset but I am unable to send my photos to my laptop through the usb connection.the photos are all a similar size and I cannot understand why most of them won't transfer to my laptop. About 40 have successfully transferred but the vast majority won't. When I go into my blackberry to view the files that way a message comes up saying that either my files are corrupted or unsupported or too large! This cannot be the case for they are the same as the other photos taken by my blackberry camera phone.

Any ideas anyone on what this problem is and how I resolve it as I don't want to lose important photos.

Thank you.