I am designing a site and want to use the images of the properties to have the main visual impact,
I have done a mock-up of the property list page

My last 3 attempts of building the site has resulted in a sub standard site that is very slow and not user friendly, this has been because I have tried to built it within the constraints of joomla and a booking component and more importantly my limited knowledge,
This time I am having the site built from scratch, so the functionality and speed should be right

but they will only implement my design
95% of our competitors use a much smaller images, most only thumbnails, so obviously this is for a reason

as i have got this wrong 3 times already I have to get it right this time
So my reasoning is
most don't have the quality of images available,
They are listing thousands where we only have 200 and when filtered down may only show 10 or so, our clients wont be trawling through hundreds,
broadband speeds have changed a lot, 76% have it and probably 95% of my target audience have it,
I will get them to just load the first 2 or 3 images then the rest appear with live scrolling, same for the slideshow with background loading,

Am I missing anything obvious?
Is there anything I should be making sure is done?

more pages from the mock-up if you can see any design flaws I would appreciate your feedback