The end investor will want a copy of the lease so make sure you get that along with a detailed list of repairs to be made.
One way around the picture issue, have the owner tell the tenant you are with the insurance company and you need a couple of pictures to verify the property for insurance purposes...or some other story along those lines.
As long as I've done all the necessary homework, I probably wouldn't be too skeptical just because the seller was a little weird.
However, it may be difficult for you to wholesale it without you closing on it first and getting the seller out of the picture completely. As a newbie, many investors may be hesitant to trust you without verifying with their own eyes. However, if you find an investor who is very familiar with that neighborhood, knows the values, rents, etc for the area, then they may be ok without seeing it.
You would probably need to target landlords who already own in that neighborhood and market to them.