Just the ??? I needed an answer to. My other prob is this. When i am done in PS what do I do next? Where and how do I save stuff? Also, must I convert my photo to a jpeg or can I work it in psd. My tools would not do anything while I was in psd. Thanks for any help .
When done with a file you were working on, and you want to save it, File>Save As...
This saves your current document to anywhere you would like, a local disc [hard drive, or optical, or Server]. The feature File> Save; Saves any changes, to an already saved document, saving changes made since opening the existing document.
JPEG/TIFF:
You can use JPEGs in PS, it just depends on the way you intend to use it/them. Since I mostly use JPEGs received from customers at work, we tend to mostly use Hi-Res JPGs or Tiff images. JPEG is a generic file format, meaning it is a Lossy Format; it throws out pixels when it can to conserve a small file size. TIFF, on the other hand is a Lossless Format type of file. Tiffs file sizes are bigger, since they tend to not throw out pixels, it replicates pixels when it can [AKA - ReSampling an image].
You don't have to convert a JPEG, to anything else, in order to use it in PS. However, if you are working with a PSD file, and wanted to send it to a Printer [Offset Press Printer] then most people would Merge Layers, or anything else in that PSD to a One Layer Image [one flattened layer], before printing it. In our office the designers are the only ones with the editable working PSD documents, the designers would output either TIFF images, or PS files.