Advanced Layerslider: Visibility problems

I have a situation I spotted on an older browser while testing an commerce site in development—it has all position-only images right now. In the development site there are simple advanced layersliders that have background images to fit a 27″ monitor—2560px X 740px, and two or three overlay layers. This works well on modern browsers so far—including mobile. I happened to view it on a 17″ MacBook G4 with Safari 5.0.6—1440 x 900 and the sliders with type layers do not show the background image. In addition the first mega menu’s background has turned black (Swing Control.) The black background shows even with a narrower image that displays fine.

I fooled around with it and found that anything over 2000 width in the background image will not show up, but under that it’s all fine. This is a problem with 27″ monitors and especially when I set HiRES, Retina images. I haven’t done a lot of testing on Explorer yet.

I also have an older G5 desktop running the same OS and Safari—the images show up fine on that machine with resolution 1280 x 1024, but the first mega menu also has a black background. The black background shows regardless whether the background image displays or not, s is its own issue—but only the “swing control” menu does it—the menu “lookbook” does not exhibit this behavior.

See private data for sample site addresses.

My questions are:

• Is there anything I can do to make sure the Advanced Layerslider background image will always show even with 2600 pixel width?
• How might I handle the first mega menu having a black background?

As I say, the site seems to display fine on current browsers so far, but I am concerned some consumers won’t be able to use it as it is a non-tech audience.

Can you help?

Thanks.

– Michael