A magnet does not affect a computer other than the [mechanical] hard drives. Even then, you'd have to take it out and run it through a relatively powerful magnet for it to do anything. Flash drives, "jump drives", or "thumb drives" are a form of solid-state storage (just as SSDs are, but on a different level) and are not susceptible to electromagetic fields.
To erase a USB memory stick, using a MAC, use the application Disk Utility. With the USB stick inserted into the USB drive, highlight that stick from the list of drives. Then select erase. It will erase all of the files on the drive and reformat it. You can also use a program called Houdini 2, which will allow you to see hidden files, move, and erase them.
The jump drive's drivers are probably not installed on your computer. You probably can google your drive's drivers, download, and then install them.
In order to you'd have to take the pictures from the computer and put it on a jump drive- usb drive - flash drive.
First you scan the pictures and save them onto a external memory drive or a jump drive. After this is done you can take the pictures out of the portable memory drive and transfer them onto your computer.
You can use a USB or a THUMB-DRIVE or a JUMP-DRIVE You can get them from JB HI FI
though an External HardDrive with usb interface
A external usb jump drive. Plug it in, open to view files, paste your file there. Plug it into the computer, view files and copy and paste it in your documents
use the plug with the jump drive socket to play on Windows Media Player
You can back up information from your computer onto a flash or jump drive. This will provide faster data recovery if you need to restore information from your computer.
First plug your device in and go to Start > My Computer and select your device, then delete the files.
c. jump drive
A jump drive provides high capacity computer file storage at a reasonable price. Jump drives can be purchased at physical stores such as Walmart, and online sites such as Amazon and eBay.