I have a layer in Photoshop CS3. How do I "cut" star shaped pieces from it (leaving a transparent hole in the shape of a star)?
Do I need to use a clipping mask, and if so how?
If understood your last question, with vector safe you only might mean keeping the "vectorial" operations inside Photoshop, as all output you have from Photoshop, is raster, not vectorial, unless you export as AI file, but that would be only paths, not fills. At least in the CS versions I know (a bit old ones). Anyway, photos aren't vectorial, so not much of a point in exporting so. If is to keep the paths related features, ie, if you resize the image, the start gets resized, and the edges of the star, will be sharp, and do a nice crop out. (although an enlarged photo adds blur by itself), or, you could rotate the star with vector arrow tool, resize that arrow shape, modify as wished, that the mask would be applied automatically. To do this:
This is the most vectorial you can go, as far as I know.If you had like 20 photo layers bellow. You could just make a group of the 20, then just drag and drop the star shape thumb (all this operating in layers list) over the group: All the layers will be masked with the star! With teh advantage that if you modify the star, all bellow will be masked according to that change :) If it's 20 or 150. You could now alt + click over each layer eye icon to visualize only that and export as png or whatever, or just use File menu, Scripts, Export layer to files.
Select layer to bite out of (A). Layer >> Layer Mark >> Reveal All.
Move your star layer over A.
Select the path selection tool. Right click the star layer >> Make selection... >> New selection
Select A in the layers panel.
Hit delete (or backspace), and the bite will be taken.
The question remains, how do I make this vector safe?