@jaska120
Had same problem when viewing on phone (iOS/Safari). I did a workaround by optimizing the slideshow image files. Saved as JPEG Medium and reduced file size from 1.4 MB or so to 100K. Now site loads fast. Going to have to do it to the portfolio images as well. The slideshow images look fine on phone, but the city/bridge image is a little pixelated on my PC monitor. The others are fine. This is an issue with tradeoffs between image quality vs. optimization for web.
I like the images but will try to go with vector files at some point down the road for quality, as retina etc. gains in popularity for mobile.
