Images for retina display still unclear

Question

I just published my first site in muse, and I used a bunch of thumbnails made from photoshop buttons. For the desktop version, they are all 300x169. For the mobile version, I made them all 600x338 and then transformed them to 300x169 in Muse. I did this thinking it would be enough resolution for retina displays, but when I view it on my iPhone 6, they don't seem clear. When I email the same files to myself and open them on my iPhone, they are clear, but not on my published page. What did I do wrong?

Answer 1

vega9, thanks for the info via private message.
I expect the manually added meta tag for width was the incorrect solution to the problem. In general if a page is resizing incorrectly on phone or tablet devices, it's caused by content being outside the width of the page. Having content outside the page is often accidental (i.e. an empty text frame, the transparent area of a widget or container protruding beyond the page edge, etc) and easily corrected.
As of the images, they are crisp 2x retina images. If you zoom in on the crisp edges and see the stair steps of pixelation, in your case I believe that's due to the limitations of creating a smooth looking edge when the authoring application of the graphic doesn't know the background color.
The anti-aliasing approach used to create a very smooth looking edge on an LCD display requires knowing the background color. If you create a transparent PNG the edges can't use optimal anti-aliasing because the colors of the pixels that will behind the edges are not known. This results in the edges using a color agnostic approach to anti-aliasing, which is far better than no anti-aliasing but noticeably worse than LCD anti-aliasing.
The short answer is, bake the background color into your images when you can and set an opaque background fill on text frames that use System Fonts. If you create a version of your logo that's an opaque image with the blue background baked in, the edges will be sharper. (Note that you'll want to turn off the automatic opaque PNG to JPEG conversion in Site Properties in Muse to avoid JPEG compression artifacts around the sharp edges. Or make a single pixel in the original PNG slightly transparent, 99% opaque, in order to prevent Muse from converting the image to JPEG during output.)