iPad was released 5 years ago. I have iPad2 and iPad air 2, and both works fine.

I don't have LG. I have tested on Asus, Samsung S3, and Nexus 5. Try it on Chrome browser, and see how it works.

Some images (Washington post, latimes, etc) are bigger than 20 MB each. All browser freezes when you render those images. My demo specifically includes those to see how bad it performance on different devices.

One of the benefit of being a big company is you can control everything. Flipboard scales down those images to 300kb before sending it to browser. I use original images.