I had already invested in Splashphoto for viewing needs, having come over from the Palm World, it was something I was familiar with.
Resco Photo Viewer is indeed a good product. While I wouldn't buy a second image viewer separately, I did buy the Utility pack, which included Resco Explorer 2003 along with the Photo Viewer. It also came with Sticky Notes, but I don't use it. /shrug/ No need. I avoid the stickies in real life when possible, ... dont' see why to stick it (pun not intended) on my handheld too.
But together, they were worth the combined price. Best feature of Resco's Photo Viewer: They have the best translation from a viewed image to a Background capture for your Today screen. They aren't too bad on the Image Thumbnail resolving, but Splashphoto is faster on that point. In this case, it would depend, I think, on what you want and need out of your photo viewer.
But give both a try. I personally think BOTH are worthy products.