You can attempt to do a bulk upload if you do not have backups.
Here are the steps I would do.
1. Rename the data directory to dataold.
2. Create a new data directory and set that to 777 permissions. Now you need to upload the photopost upgrade script to your server. Run upgrade.php and select the 4.85-5 upgrade script and run steps 1 and steps 2 dont worry about any duplicate errors. Your running this to create the data directories for all your cats all over again so you can upload to your data directory. You can ftp to the server and make sure your directories where all created. If so go to next step.
3. You can go to upload screen select the proper category and hit the skip upload checkbox and fill in the proper server path to that specific directory say if you where uploading to your category 537
Then hit submit and it will scan that old data directory for images to upload. You can then fill in titles descriptions when the program processes the files. You need to do this for every category to get those photos back since you dont have backups. When you have everything reuploaded you are safe to delete the dataold directory.