That's strange, I have had no problem with using png's in my programs!!
Which version of delphi are you using?
If you want to use other components, its easy enough, just a bit hard to work out (took me a good few months!!)
- Copy all the files relating to you delphi version to the bpl folder in the default save location for projects (it differs depending on the version). If you dont know which are for your version, copy them all!!
- Open the package file, should be a .dpk file
- Compile it.
- Under the project menu there should be an install item, click it.
- The components should appear in your pallet.
NOTE: I think delphi 7 personal is missing a file needed for most components. I can remember what its called, but let me know if you need it and ill email it to you.
Hope it helps
Gary