Equirectangular and cube pictures
We have used the following two formats for showing 360 degree photographs of Frodsham:
Equirectangular spherical format is the easiest panorama for us to make, since it consists of a single source file in 2:1 aspect ratio. Many mobile devices have a MAX_TEXTURE_SIZE of 4096 px wide and won't load WEBGL textures larger than that. Unfortunately, trying to stretch 4096 pixels around a full 360 photograph results in poor quality. We upped this to 8096 pixels. However, the disadvantage is that you have to wait for the entire image to download into the browser before you can display it.
This format has a few advantages over the equirectangular format that includes progressive loading on demand, multiple levels and resolutions to fit your device's browser display with no size limits. The pictures are dynamically rendered. We use images of up to 17,000 pixels wide. Although more work to prepare, it does adapt better to your device and offers more detail.