Travelify featured slider and image problems

Hi;

I’m having trouble uploading images which are sharp (not blurry or pixelated). They look fine in their original format but as soon as I load to my website cantravelwilltravel.com, they become really unclear. You can see this in the on the home page, the background and the

I’m sure it’s something to do with the size/ format of the image when I upload them. Can anyone advise what I need to do to edit the images before uploading and what I need to do when loading/ adding to a page to ensure they are clear.

Also on my home page – I’ve added a featured slider which referenced a featured image from a page I set up specifically for this. However I can’t get the full image to show it is cutting off about a centimetre from the top and bottom.

Any suggestions how I can fix this please?