Is this vein above my ankle that enlarges when standing ankle problematic? (photos)

The bulging vein is the most distal part of your greater saphenous vein and is normal. I would obtain a diagnostic ultrasound to see if you have more proximal reflux. Best, Dr. KaramanoukianLos Angeles

Consider a vein specialist that is able to recommend the best treatment for you according to a full evaluation including ultrasound results. Without treatment of venous insufficiency, those with the disease may experience progressive symptoms like leg swelling, skin damage and/or ulcers that can debilitate and impact a great deal the quality of life; however, that outcome is preventable with proper treatment if indicated. According to the type of treatment a patient may resume normal activities fairly quick. 
All the best, 

What you are showing is a prominent great saphenous vein. You may have segmental reflux of the GSV below the knee. Seek guidance from a vein specialist and take a citrus bioflvonoid formula that promotes vein health (see link).
H Karamanoukian MD FACS
certified vein specialist from ABVLM

I would only be concerned about the vein if it was causing you discomfort or you were suffering with pain, swelling, fatigue or heaviness in that leg, which are all symptoms of venous disease.  If not I would simply advise you to follow up annually to see if the reflux is worsening or the vein is becoming more enlarged.  If at anytime you become symptomatic, then I would consider treatment.

The posted picture is a normal distal great saphenous vein and is common in many people.  As you stand the veins fill with blood and the vein may appear distended.  This is normal.  I agree that your reflux appears to be insignificant.