Picasa is a pretty nice little program for organizing your photos and can’t be beat if you compare the price:performance ratio. However, it’s not perfect and one of the ways it’s lacking is when trying to move your photos to a new location either on the same computer or on a new machine.
The easiest way is to ask Picasa to do a full backup of your photos and then restore that backup in the new location. However, this is not feasible when the photos are mixed in with your general user data or you’ve already transferred everything and just want Picasa to reference it as it did before.
The problem is that Picasa stores its database hidden under “Application Data” for the current user (in accordance to Windows style guides) and keeps only “starred” status and edits in the “picasa.ini” file in the directory alongside the files stored there. Thus, just moving your files won’t move this database. Instead, you need to do the following:
1) Go to C:\Documents and Settings\MyLoginName\Local Settings\Application Data\Google\Picasa2Albums and copy everything here to a scratch location on the new machine.
2) In the oddly named directory (an apparently random bunch of letters and numbers), edit all the .pal files and replace everything between <DBID>…</DBID> with the string “null”.
3) If the pathname to your photos has changed, do a global seach & replace to fix the pathnames in this file.
4) Close Picasa on the new machine.
5) Copy the modified .pal files to the oddly named directory at the same path on the new machine (note that the oddly named directly will be a different apparently random bunch of letters and numbers).
6) Start Picasa.
7) All your albums should now appear.
If they don’t, or some don’t, then one or more of the photos referenced in the copied .pal file(s) was not found among the new photos on the new computer. Picasa rejects (and deletes) the entire album if even a single entry cannot be found. This can happen because the files exist at a different pathname, don’t exist at all, or simply have not yet been scanned by Picasa. In the last case, it may just be a matter of marking all relevant folders as “scan always” and then restarting at step #4.
Since I work at Google, I sent an email to the Picasa development team and we talked about some ways of fixing this problem. Hopefully it’ll get better soon.