Synchronizing. This is very very important. There are a lot of free programs you can download off the net to help in this endeavor. I tried SyncToy, but didn't like it for some reason. It felt like it wasn't doing the right thing for me. Then I tried Allway Sync, and have been pretty happy with the program. It allows you to preview what it wants to synch and then you can change individual files by telling it to leave a particular file alone or to change the direction of the copy. It is fairly intuitive. The most important thing is to make backups of everything so that if anything goes wrong you can always go back to the older version. Make sure you understand what it is going to do before you hit that "synchronize" button. Trust me.
Another thing I have been trying to do is to put the copyright information on all of my images so that in the corner there will be a little "copyright K. T. Ryder Wilkie 2006" on each photo. After much shenanigans, I discovered that this can be done somewhat automatically in photoshop. I have an old version of photoshop and I was worried that this option was not available, but it is. Try this website for a tutorial. The one thing I would caution anyone about is that the font shows up differently depending on the size of the file, so you need to monitor each one as it is added to the picture and decide whether or not to accept the change. You might have to do several separate batches for differently sized images. It is definitely faster than opening up each image separately and adding the information manually, though.
Right now I am trying to figure out a fast way to delete all of the images (most of which are wrong or outdated) from my Mantis database and then upload all the new ones quickly. So far have had no luck. It appears that the only way to do this is to individually open up the species file, click on each individual image, delete it, and then upload each photo one by one back on. This will take forever, and I am stubbornly refusing to admit that there isn't a better way. There are rumors of a new version of Mantis, so I am hoping maybe that will improve the situation, but am not sure if waiting is really the logical thing to do. So I thought I would work on my blog instead.
Speaking of databases, there are a lot of programs out there made especially for taxonomic work. Here are some webpages and PDFs with more info:
I personally have never used anything besides Mantis, but am fairly happy with it. Some problems I have had include the issue I just mentioned above about ease of importing images and issues with the label function not working right (although having a label function at all is fantastic!). There is supposedly an updated version coming out soon so I am hoping these issues will be addressed.