I think it is always best to add the file name type: .JPG or .JPEG, .PSD, .TIF for Windows (Mac OS recognizes .TIF or .TIFF with two F's) and so on. it can help in a number of ways, such as searching external mdia or ecternal drives, and so on. Under older Macintosh OS protocols, every file has a hidden "resource fork" which identifies the file's creator (Adobe Photoshop, or Illustrator, or Capture One,etc) and also the file type, like .JPG, or .PSD file, or whatnot. That was, I think, the root of the issue that I experienced when I sent files I had edited in photoshop to the Koak printing-out machine, which was run under a non-Macintohs-OS system; while my macintioshj computers could read the hidden resource fork data, and "knew" the file creator application, and also the file's type, the Kodak printing machine had difficulties.