Thank you for the pictures as it always helps to give a better answer. And looking at a few of the other contributors, they have already given very good information. You will definitely want to use a laser that can attack the colors using four different wavelengths. We use the StarWalker by Fontona and it includes four different wavelengths and a proprietary FracTAT™ procedure, that pretreats the tattoo with an ablative Nd:YAG that creates little holes or chimneys in the dermis that allow the escape of gases from the photoacoustic explosions from the pigment destabilization. Ink spray can actually come out these holes so there is less ink for your body to break down, and you can do several passes in a session. Alternatively, pretreatment with a fractional beam like Erbium can create a similar result, though the Nd:YAG is more pigment specific. Both methods also minimize risk of scar formation.
The StarWalker is capable of delivering an unprecedented 10 J of Q-switched energy in one giant structured MaQX pulse for treating epidermal and dermal pigmented lesions. The StarWalker thus combines the high energy capabilities of nanosecond lasers with the ultrashort pulse peak powers of traditional picosecond lasers, the best of both technologies. Whatever laser you use needs to be Q-Switched and preferably have picosecond pulses.
The treatments can be done with a chiller, but as large of area as you have, needs to have lidocaine and probably should be done in two different area treatments, like one day the leg and another the thigh. The pretreatment, as above, allows several passes in one session so you get more pigment reduction without too much heat or tissue injury. I hope this is helpful in try to get the quickest and safest result for your tattoo removal.