The obvious method is to construct a loop to read filenames, inside it, open and read, then accumulate the data content in some file you select. You need (maybe) to have a certain way to distinguish between images data if they are to be joined in a single data file, and you must think of such file to be relatively large to handle.
If filenames have some sequence then it is possible to automate the reading loop easily, if not, however, you might consider renaming these image files. Other than this I can't understand a method to read many files with vast differences in their names automatically.
Also, as Walter ans Jan said above, if non of these answer give you an idea about the solution you seek then please elaborate your problem with more details, as filenames to be used in reading, data type you need to store, and the format of how you need to write them..etc.