thought you might have been on to something with the delete icon, I hadn't tried that before. So I made an image 10px by 10px (300 bytes, yes bytes not kilobytes) then saved it as a jpeg at 0 quality, ie max compression. Once closed the file when viewed in the finder is still 32kb, then I delete the icon and I can get it down to 16kb. still no good.
so somehow a 300byte image saves as a 32kb file. I have no idea what's in the rest of the data.
This is to do with block allocation, an empty file on a 32 bit filesystem will take up 4Kb of diskspace. Disks are divided up into blocks.
Ignore what the operating system is telling you and try and upload the file, the system should allow you to upload and then it will check the size of the file as is being reported by the filesystem it is on (Linux, probably ext3 or ext4), which is a better system.
Typically, as disks got bigger, they increased the size of the block allocation, which meant that smaller files take up more space, but there is less overhead.
James