Why do I look lke this? (example pics)?

I have the exact same problem!! my is a size 12/14 but the rest of me is a size 6/8!!! UK sizes btw lol. It is stupid because when I am at the gym I only work my legs and theighs but all my weight just comes off my and arms which I don't need I look too scrawny! what I find helps is drinking plenty of water and fruit and veg etc...but also walking alot helps as well i found that since i started living in town where i walk EVERYWHERE my legs have really slimmed down and so has my it is getting down to a size 10/12 which is ideal :) good luck :)