Try preshrinking your file prior to sending it to them.
I know Canon DPP has a batch resize function. So I get all my photos the way I want them and then batch shrink them down to 800x600
before I send it to them - so the file size goes from 8MB to 200KB. Anything bigger than 600 goes off the page and you end up scrolling anyway. PLus you can store a bunch more photos that way.
That said I was curious if I was losing any resolution because I thought they looked about right so I checked their FAQ. Full details
here- seems they keep the file, but post a condensed version.
What camera are you shooting? The software should have some type of batch resize on it.
BTW - take a look under "Upload" you'll see a "Customize Upload Options". You can tweak that a bit too.