UPX is a command-line utility that helps you reduce the size of both EXEs and DLLs

UPX is a command-line utility that helps you reduce the size of both EXEs and DLLs, allowing more programs to be packed onto a USB drive.

No additional software is required for the compressed EXEs or DLLs to work. An additional benefit is a potentially faster loading program due to fewer read cycles to load the EXEs/DLLs.

UPX Tool+ is completely portable.

UPX Tool+ is a GUI wrapper for UPX for the command-line intimidated. It includes UPX v3.00 and it is possible to compress with LZMA (a better file compression format).