I don't recall ever having seen a Word document that would fit in 255 bytes.
I just created a Word document containing a single letter ("a"), saved it to disk, and found a file size of 29KB. That was Word 2007 BTW.
The only type that is suited for storing binary data IMO is a "blob".
MySQL offers blob, and some size variants thereof. Use those. I never used "binary".
Yes, saving and retrieving data to/from a database is tricky; as long as it doesn't work, it is hard to tell where the problem lies; it could be in the saving part, or in the retrieving part. And when you have several bugs at once (I'm sure you do!) fixing any one of them doesn't seem to help at all, until you get to the last one.
The good thing is, you have to solve it only once, as it would apply to any kind of data, as long as it fits a byte array model, it is all the same.
And the best thing is, millions of people have done this before, so the solution is bound to be available everywhere you look.