TIFF file is not compressed when you scan to network
Scan to network; Scan to PC uses compression CCITT G4; With the N2501e and N2601e MFP systems, compressed TIFF requires a Lexmark program on the receiving end in order to "fix" the image. This means that Scan to EMAIL and Scan to FTP will not use compressed TIFF. This is a limitation of the MFP that cannot be changed due to memory constraints.
As a workaround, consider using a file format other than TIFF. JPEG is always compressed and PDF is usually compressed.