I used a Naked Hosting shared plan for galleries (before I got a dedicated server) and I didn't have any problems. Of course, it's going to depend on how many galleries per day, how much traffic each gallery will get, amount of content, etc. I was doing around 1-2 photo galleries a day from there. But it was able to handle listings at Hun and Worldsex without any problems.
I would recommend you add "Certified Protection" to your shared hosting plan. It's an additional $4.95 per month. If you're abusing the server, they will move you to a dedicated server. So you won't get suspended or have to worry about major downtime. You'll have two weeks to either get your shit under control or upgrade to a bigger plan. And if you upgrade your plan, everything you've spent on Certified Protection will be credited toward your new plan.
Here's more info (Certified Hosting and Naked Hosting are the same company):
http://certifiedhosting.com/protection/