Image dimensions does matter

In the past, we only need to be concerned with file size reduction for our web pages. But, according to Stuff and Nonsense, image dimensions is another concern. Especially on iOS. Why ?

Stuff and Nonsense blog notes that when including large images on their portfolio, some do not render correctly on iPad.

These are content images rather than CSS background images and they’re unavoidably big (I think) as I’ve used double size dimensions for high-resolution screens. I wish there was a better way but, you know, responsive images. (I’m also currently experimenting with Scott Jehl”s picturefill but that’s a story for another day.) For example the first Pairoo image is a super sized 2852×2319 pixels. Where it makes sense for the image, I used pretty highly optimised PNG images to reduce the file size as much as I could too.

The large images displayed correctly in desktop browsers but not on my iPads, unless I reduced the pixel size of the images — I learned this through swapping different images in and out — or exported them as JPGs.

Source: Stuff and Nonsense

Now, after some searching, they found on Apple Developer Library that there is a limitation on the image dimensions. The image dimensions must be less than 3 megapixels for devices less than 256MB and less than 5 megapixels for devices more than 256MB.

So, next time you are including a large image, do take into account its dimensions, not only their size.