This is a small snapshot of 4 men and their bikes. On the back someone has handwritten "Summer of 1938". The two bikes on the right appear to be Harley Knuckleheads (either '37 or '38) - you can see the roll bars on them. The one on the extreme left may also be a Harley, but the one right next to it is probably something else.
The photo has lots of creasing, but it's still an interesting image. Old time Harleys in the field, raising a ruckus no doubt.