The prices are excellent if you have a small number of images read/processed many times over a month. If you have a large number of images touched only a few times a month, it's horrendously expensive.
For example I can thumbnail ~7M images in ~2 days on my dedicated machine (40/s) which costs me $60/mo to colocate. $60/mo gets me a paltry 20k images from Imgix (though admittedly I can process them multiple times for the same price, I don't need to).
Right. In my last two jobs, one of them had a relatively low volume of images (let's say, around 30k being requested per month) scaled to an arbitrary number of transformations, whilst the other had a high volume of images (millions) with a low number of transformations.
In both cases, the cost of doing it ourselves (using something like thumbor) would have been a few thousand per month. In the former example, imgix cost a few hundred, in the latter it would have cost in the hundreds of thousands.
imgix is the fastest of the services i've looked at (transformation time is roughly half what I got from cloudinary, and average response time is also about half), but its pricing model means it's completely unaffordable for certain types of product.
Disclosure, I am from imgix.
If you start to exceed $500/month we can offer discounts and certainly when you are looking at millions of images then a flat rate at a lower level makes a lot more sense. 30 million unique images certainly should not be $90,000, that would be outrageous.
The $60 above doesn't include bandwidth from either my transit provider or Imgix, you can purchase a CDN separately.
Imgix is 8c/GB which is certainly competitive but by no means unique. CloudFront is only $0.005 more expensive on the higest tier and gets as low as $0.02 on the lowsest. A cheaper CDN like CDN77 starts at $0.049/GB and goes as low as $0.007/GB.
Cloudfront charges for requests and it can often be the biggest component of your bill.
CDN77 performance in terms of latency is not that great. If you are looking for a cheap CDN with good performance, buy edgecast from a reseller. The only problem with edgecast is that they charge a really high fee for SSL support for custom domains
For example I can thumbnail ~7M images in ~2 days on my dedicated machine (40/s) which costs me $60/mo to colocate. $60/mo gets me a paltry 20k images from Imgix (though admittedly I can process them multiple times for the same price, I don't need to).