Not just hotmail. Most web mails and e-mail clients don't allow attaching a folder. They only allow attaching individual files.
Another possibility using e-mail: Put all the images to be sent in a ZIP archive, or any other format available to you as TAR, 7z, BH, ARJ, RAR,..., and send the archive.
If the computers are at the same location, there is an even beter option:
Connect them over a local area network (LAN), set a folder on one of the computers as shared.
It can be whired or wi-fi as best fits your situation.
It CAN be the actual folder containing the images you want to transfert, or the folder that is destined to receive them.
If the folder is on the laptop, from the desktop, drag and drop the images to the shared folder.
If it's on the desktop, COPY the images there (not needed IF the original folder is the shared one).
Next, from the laptop, open the shared folder and drag the images to where you want them.
There is no real risk involved as ONLY the shared folder is ever visible to any other computer, and then, only to those connected to the same LAN.
Electro, November 2011