Rock sizes follow a regular distribution of some sort, most likely a power function / Poisson distribution. So, nearby, you'll have a lot of smaller rocks, further away you'll have a reasonable number of larger ones. For moderate-field views (such as the image shown) this may not show much difference.
Other factors of the moon: there's no weathering action, absent meteor impacts and very slow microparticle weathering, but this is taking place over hundreds of millions to billions of years. Where rocks of different sizes on earth will weather quickly (tens to millions of years depending on rain, freeze/thaw, wind, organic (lichen, bacteria) actions, etc.), this doesn't happen on the moon.
Upshot: near small rocks look very much like far large rocks.
And again, in alpine or desert landscapes without notable organic features (plants, animals) or human structures (roads, buildings), it can be very, very difficult to estimate range.
Other factors of the moon: there's no weathering action, absent meteor impacts and very slow microparticle weathering, but this is taking place over hundreds of millions to billions of years. Where rocks of different sizes on earth will weather quickly (tens to millions of years depending on rain, freeze/thaw, wind, organic (lichen, bacteria) actions, etc.), this doesn't happen on the moon.
Upshot: near small rocks look very much like far large rocks.
And again, in alpine or desert landscapes without notable organic features (plants, animals) or human structures (roads, buildings), it can be very, very difficult to estimate range.