It's best practice to adopt good file naming convention for your images. The key concepts you need to bear in mind are:
- Every image in your Library should have a unique file name.
- Your online files should be named identically to those in your catalog.
The latter point implies that you should have an understanding of how your DAM application handles file naming on export. For example, Lightroom does stupid things when naming its virtual copies; to avoid unnecessary frustration, you should not use its virtual copies in your albums.
If using software other than Lightroom, then simply beware of cases wherein the software renames or appends to your image file names, such that the exported image name will not match the file name in your library.