fix wordpress image size problem

i want you to fix images problem in my wordpress , all you need to help me with each section of wordpress where we will upload different images but now problem is that images are not in one size so i want you fix the issue so whatever size i upload it has to show me the one size for thumbnail and one size of its popping up image , all i need you do professional work. here is example of what i am looking for [login to view URL] Pm me if you are interested and if you can start right away for further details