wazz

hi, i'm trying to change an image's main color (see attached). the image has a white, wavy "thread" running along the bottom. is there a way of changing the green to another color and keep the white thread? i'll have to eventually make several versions of different 'main' colors, all keeping that 'thread'. [the actual image is 3000 x 600 px; a continuous 'wave' pattern like the sample.] tnx.