While learning all about JPEG 2000 for the Promo images. I found out that the WebP image format actually supported transparency, which we currently need for our game icon images. Also not only is Google suggesting to use WebP as an image format as it did with JPEG 2000, WebP is an image format built by Google. Best of all I can detect when WebP support is available and fall back to png if not.
Unfortunately, with JPEG 2000 I wasn't able to find a way to detect its compatibility. More importantly the information on it's compatibility with browsers doesn't seem to be correct either. From what I have found it is said to only be compatible with Safari. Where as I tested in Chrome, Microsoft edge and Internet explorer which all seemed to work perfectly fine.
That being said I can detect WebP compatibility so for now I only allow JPEG 2000 images to show if WebP is enabled, if not falling back to .jpg. For now I am going to presume that any browser keeping up with the times have also added JPEG 2000 support. If that doesn't appear to be the case I will just change promo images to use WebP format too as it won't really make a difference and could be the better option all round.
Like with the promo images you don't have to do anything either, WebP versions have been generated for all Logos and Icons. Which will be used if compatibility is detected.
EDIT: Well after some testing, it seems that WebP is a considerably lower file size then JP2 so I have decided to make both icon and promo images display as WebP if compatible. If not they will fall back to .jpg and .png like before.
Thanks,
-iDev