You should have said that you were using Adobe After effects.

Hopefully you should have named your images as "file_name_0001.extension" going up to say "file_name_0500.extension" for 500 frames.

Then open After effects, make a new composition, then file import select the frist image then check image sequence and import.

Then drag and drop it into the comp window, the image sequence will then be imported as "footage"