I have a Sony Ericsson phone with Android 2.3.4. I take pictures with it and when I want to get them on my PC (to use them on my blogs, etc...), I just connect it to the PC with a standard USB cable and go to Computer-Phone-DCIM-100ANDRO.
Never had any problems with it until recently. A month or so ago, when doing it, I got 10-20 photos displayed in the directory while my phone had several hundreds of them. I tried many things like restarting my phone, restarting my PC, I even deleted some photos to see if it would help. Maybe there was too many of them... to no avail. some photos simply did not show up in the 100ANDRO folder.
I googled the problem a bit, found many people having the issue, no matter the phone (even some with the iphone had it) and the only solution I found was to change the transfer protocol which did not help me at all. I played with the phone settings and... I wasn't able to transfer anything anymore.
At the end, the only solution I found was to use dropbox. It lets you transfer pictures from your phone to your dropbox space which is available from your PC.
Maybe not the perfect solution as it takes some time to upload the photos I take from my phone but retrieving them from the PC is immediate and available through normal web browsers.
I still use the traditional cable solution most of the time but when some images are missing, I use Dropbox.
Just thought I would write this post to help those in my case. You will notice that I don't even include a link to Dropbox. My aim is not to advertise a particular app/software. But this saved my day (well my photos at least) so they deserve to be mentioned.
Good luck with your photo transfers!