Dude, I'm pretty much in your exact situation right now. I've hit a wall too and monetizing through Adsense isn't going as good as it used to.
I'm currently using CrazyEgg to heatmap my website and place ads according to that and also using the stats on Adsense to find out which ads give me the most money/clicks. I've found that no matter how I place my ads on category pages, no one is interested in them. My CPC is low too so that just seems to be the problem. I don't get as much pageviews as you in a day, so you should definitely reassess your ad placement. Take a look at using CrazyEgg, I'm on a 30 day free trial right now. Map out how users look at your site and change ad placement based on that.
it is not always about ad placement. It has to do with relevant ads based on your content. Less content = less ads that people want to click on. It is not about tricking your audience it is about engaging them with offers and services of similar value to what you offer.
P.s Image sites suck balls. Don't bother to get involved in that mess
try a floating banner , best ad size is 160x600
I seen lately few sites has floating adsense banners and until now still runningAren't floating banners against Adsense TOS?
With image sites the best way is to use an ad rotators PLUS 1-10 slide that the page refreshes everytime they hit next. This creates ten page views. 1000 page views = small but yet a payout indeed.
The 1-10 is basically a "See ten pictures of why you should sit when you pee" Then show one picture and then force them to click next 9 more times to cycle through the rest.
Just an Idea and my opinion .