Low resolution/detail tiles for old devices

I have a Garmin GPS V. It is super old, but still works perfectly, and I can still successfully load OSM tiles onto it from http://garmin.openstreetmap.nl (A great service) using Garmin MapInstall.

The problem is that the GPS V doesn’t have expandable storage and is limited to only 19MB of tiles… which is about three tiles.

Is there anywhere I can get (or make) tiles with less detail, or lower resolution, so that I might be able to fit more than three tiles onto my device?

It’s for a different device, but you might find the process described at http://www.openstreetmap.org/user/robbieonsea/diary/41933 helpful.