I load a gif into photoshop as frames. It is about 200 frames, and I want to add some extra text and drawings to about 100 frames.(The same text and drawing in the same postion on all 100 frames.) How do I do this without drawing and adding text on every single frame seperately?
howdytom is correct but as you already have 200 frames the easiest way to add extra text/drawings to some of those frames would be to do this on a new layer. Then within the timeline window select the frames (these are shown highlighted -- use [SHIFT] to add to the frames selected if frames are alongside/next to each other; or [Control/Command] if frames are spaced apart.) and either hide or show the new layer.
If you want to make a transition from "no-new content frames" to the "new content frames", then do this after choosing which frames show/hide the new layer by selecting a frame that has layer hidden, allowing a couple of frames between then selecting a frame that has the new layer shown and clicking on the "Animation-Frame Tweening" button (bottom of timeline window). This will cause the new layer content to appear to gradually 'fade-in'.