I'm looking for the cheapest company to get postcards printed.

Make sure to read the fine print.  

Have it printed, highlighted, and readily accessible.

You may however need to have someone scan through the prints you buy and make sure they line up with what the codes are in your jurisdiction.

Do I need to print the pictures out and get them signed by the tenant as well? 

Each unit has the same foot print.

Some nice paintings and art prints (gallery quality) could be consigned to a local non-profit upscale consignment shop that splits 50/50 and they donate their proceeds back into the community to support local non-profit service agencies.  

Hopefully I will not get in trouble for ask this question if I do I will delete I am wanting to know what software is everyone using to print out receipt for your customers when they make their rental payments thanks in advance 

(This is a twice verification process)  I print out a copy of the entire lease agreement, e.g., I have one for me and one for the Tenant to keep for their records.

I suggest you go to irs.gov and print out the form 1040 schedule E, and categorize your expenses according to the form instead of a general catch all "operating expense".