Any given USB memorystick should be able to handle several 100.000 writes / reads.

A harddrive would be a better choice, but I dont think you will encounter problems with the USB Stick.

You can either do as you write - place the pics in /tmp - or you can get yourselves a harddrive instead of the USB Memory device :-)

...or you can just use the memory stick, and hope it works. My guess is that you wont see problems for as longs as you are using it. Hardware tend to outdate before it breaks these days :-)

Reference: http://en.wikipedia.org/wiki/USB_flash_drive#Weaknesses

/tmp is RAM

All other mountpoints (except the ones you made for usb flash drive) is in the Flash chip in the device (like nvram - which is in a dedicated area of the flash chip).

I guess an easy way was to place the images in /tmp/images and then make a symlink in /www like this:


But when you reboot the router, the images will be lost !

I've been thinking along the same lines, but was told off by someone working at Kingston:
These flash memory devices have their own load-leveling software on board to even out load to all parts of the memory. Using JFFS2 would be counter-productive, since the load-leveling algorithms in the filesystem and on the stick will work against each other.
Use any non-journaling file system on the flash unit - ext2 would be a good choice.
Or adopt my layout: I am using two flash sticks in my routers: one for more or less static data and one for often changing data. Then I use a cron job to backup data from the often changing flash onto the other one every 4 hours. I also have that done before a controlled reboot of the router. Thus I loose only 4 hours of data in worst case, and I dont have to have an expensive, noisy and eventually unreliable hard disk. Flash memorys are cheap nowadays - I pay 180SEK for 1Gb ~20EUR, so I can afford to change the often changing flash when it fails - but it has not failed yet.