Create graphic files for game

I need 3 .png files that have the same graphics with different resolutions. Attached are the 3 files I need (but after you modify them). This is for a game I am trying to build so I will need all rights to the graphics when complete. The idea I have is to try and make the graphics as "real" as possible, with a theme, while keeping them in the smallest files. I will also need each graphic created in a separate file so I can import them into a sprite sheet. My thought is to have 3 main scene's within the .png file: 1. Outside, on a street and in a neighborhood with houses and cars. The travel road, where the player will run, will need to be in two graphics. This will allow one graphic behind the player and the other in front of the player, making it look like the player is traveling down the road. I will need obstacles that will need to be created. (i.e. cars, trucks, school bus, trees, shrubs, mail boxes, etc...) 2. Inside a warehouse or factory 3. In a forest All the images should fit together in each scene so when one block is copied and pasted onto the map, another next to it will look right. When this project is completed, there is a need for another project of similar nature. I will need the main character and the enemies created. Also, if the project continues, I will need new scenes as well. As this is a hobby, my budget is small. This is a project to get my 30 year old son and my 16 year old grandson all together to build this. I am excited and hopeful that this works out for bonding reasons.