Some Macintosh Files are "aliases", meaning that its file content is interpreted by the Mac OS as a (generalized) filename referencing a "target" file. Double-Clicking (opening) an alias file actually opens the target file referenced by the alias file. Software can distinguish alias files from other files, if desired.
It appears to me that Mathematica's Import function is oblivious to alias files, returning errors such as: Import::infer : Cannot infer format of file "logo.jpg". A search for "Alias" in the help system returns nothing relevant (IMO). Is there any workaround? I can imagine dropping briefly into C-code, but I've never done that before and the scheme seems fraught with complications.