Here is how you can do this for a text file, I havenot tried with bmp etc.
1) create a temporary table with a column which is BFILE
2) create a directory (oracle directory) for the path in which your file exists
3) insert a record into the temporary table with your file in the BFILE column.
4) Now your file is in BFILE column, you can read, display , manipulate your file using DBMS_LOB package. But your file is still in operating system location, oracle stores only the locator infomation. You can load this file in oracle completely into a BLOB column using DBMS_LOB.LoadFromBfile procedure. BLOB can also be manipulated just like BFILE. only difference being now it is stored in oracle tablespace.
Hope it helps.
Hope