The various BLOB formats (graphic, binary, and so-on) really don't say anything about what kind of data can be stored in them. As far as the file-format is concerned, they're all simply "storage space." The preview-area, which is what you see in an ordinary table-view of the field, is really an entirely separate area altogether.
My frank recommendation is that BLOB fields really aren't a very good choice for storing large blocks of data. Not only is the 2-gigabyte architectural limit "rather limiting" these days, but the overall storage format is rather precarious. A filesystem does the job much better. A database is a great place to store a file-name, if you catch my drift...