Importing several product images - No. 2+ are fine, but 1st image won't import/save

[peskywinnets]

So I'm carrying out a product import - specifically images...have all my photos uploaded to my server, have the paths all set in the csv file (e.g. http://mywebsite/myimages/product_a/1.jpg,http://mywebsite/myimages/product_a/2.jpg) ...it all works fine...i.e. images import for all products, except for the first image each time (for each & every product) - this is bizarre are the first image is no different (naming is 1.jpg, 2.jpg, 3.jpg etc)...I get an error message for each product during the import "unable to save http://mywebsite/myimages/product_a/2.jpg"     ...any ideas?

Also isn't it possible to nominate the 'cover image during' an import? (or does the cover image default to the first image imported ...which in my case isn't happening, so I'm ending up with the wrong cover image)