What type of veins are these and how to treat? (Photos)

From the photos, these tiny vessels appear to be quite ordinary "spider veins," in actually dilated capillaries or telangiectasias. For decades, these tiny blood vessels have been treated with sclerotherapy, or the injection of a solution (a sclerosing solution) that causes these unwanted blood vessels to scar over shrink and then disappear. More recently, expensive lasers and other light-based devices have been used for this purpose. However, the hard science to substantiate the superiority of these approaches, as compared with time tested sclerotherapy, is woefully lacking. A healthy dose of "buyer beware" is strongly suggested when considering these expensive "gizmos." Hope this helps and best of luck.

You are asking the right question because we always want to ideally start with the correct diagnosis THEN consider the correct treatment. But regardless of the academic name of the vein used (I.e. spider, telangectasia, reticular, or varicose vein) what matters more is where is those veins are starting from or draining into. I recommend a good quality ultrasound to see if these are tributaries to an anterior accessory saphenous vein, lateral incompetent venous perforator vein, or even associated with a posterior thigh extension vein.
Once any underlying source vein(s) are identified and treated, the visible veins may appear less obvious. Since the visible thigh veins are not bulging surface veins, to directly perform sclerotherapy on them, I find the assistance of a Vein Light to get the best technical result because while they are beneath the skin, they also are generally too close to the skin for standard ultrasound guided sclerotherapy.

Boston, Thank you for sharing your photos. Those are spider veins . The official medical name, is telangiectasias and they are small dilated capillaries and venules. They are common. Up to 60% of women have them on their legs. Your observation that they look like areas where you were bruised is spot on. They are often caused by bruises.
The best treatment for these veins is sclerotherapy. It is the most versatile and effective treatment but it takes multiple treatments to clear the spider veins. Cutaneous laser can only be effective on the smallest veins.