Generating a Neighborhood Picture

[gazania]

I downloaded a great neighborhood map. I really like it ... except that the creator is new to uploading and didn't include a PNG to use on the neighborhood screen, so I have a green grid picture instead of a neighborhood picture.

I remember having a similar situation before and generating a neighborhood picture. It wasn't hard, as I remember. I just can't remember how I did this, or where I went to learn to do this. Could someone point me in the right direction? Thanks!