How Optimole counts the number of optimized images
Optimole has two metrics which we count
- Image size quota - it measures the original size of the image. For instance, if you have an image of 1MB when someone views your image, Optimole process the image and delivers back a 100KB image. In this example, the image size quota will get down by 1MB and viewing bandwidth by 100KB2.
- Viewing bandwidth - It measures the size of the images that we send back to your visitors, cached or uncached. For instance in the previous example, when the 2nd user views the same image at the same size and browser, we will decrement just the viewing bandwidth with 100KB as the image will be served from cache and the image size quota won't be affected.
How do you count images? Why the image size quota is larger than all the images that I have on my site?
Mostly #1 is measuring the processing power that we use to deliver the optimized image. Each image is not optimized just once, it optimized multiple times based on the browser or viewport that the user is using.
For the sake of the examples, let's imagine that you have only one image on the site, of 1MB. That's the source image that we will use. Based on my first explanation on how #1 is counting I will share some possible scenarios for your site.
- One user is viewing your image on a desktop machine with Chrome browser. Your image container has on desktop 600x600 and we will deliver the image as WebP which is the best format for this browser. We will increment the #1 metric with 1MB for this case. All the upcoming users who use the same browser at similar resolution will get the same image, cached, without incrementing #1.
- Another user is viewing your image on a desktop machine with Safari. Your image container has on desktop 600x600 and we will deliver the image using the original format, as WebP is not supported by this browser. This will require another transformation that will increment #1 metric with 1MB for this case.
- Another user is viewing your image on a mobile device with Android with Chrome. Your image container has on mobile a smaller version of 200x200 and we will deliver this using WebP. This also will increment the #1 metric with 1MB.
- Another user is viewing your image on a mobile device with Safari. Your image container has on mobile a smaller version of 200x200 and we will deliver this using the original format as Safari does not support WebP format. This also will increment the #1 metric with 1MB.
Those are just a part of the possible optimizations that can be done, more variations could be found based on your website layout and how is built.
As you can see we optimize as best as we can each image contextually based on the user device and screen. Due to this fact, the same image might be optimized differently based on your visitor's details.