A slow site is bad. I think we all agree on that.
Research shows a 1 second delay in load time leads to:
- 11% fewer page views
- 16% decrease in customer satisfaction
- 7% loss in conversions
In fact, there are loads (pun intended) of studies showing how load time affects important metrics — like conversion rate.
A faster site yields better results. In plain terms: more conversions, more page views and happier customers.
So, how can we speed up our sites?
Compressing images is a great place to start. It’s simple logic. A small file loads quicker than a large file.
By using an image compression plugin, you can reduce the size of images without the hard graft.
But, what is the best plugin to compress images? We’re going to look at a few, but before we decide, let’s determine a few criteria to give us a bit of context for evaluating them.
What are we Looking for in an Image Compression Plugin?
1. Automation and Ease of Use
Automation and ease of use = making it as easy as possible to compress images without significant or repetitive manual input.
Think about it: we have roughly 400 articles live on Authority Hacker. If you make an assumption of 10 images per article, then we have around 4,000 images.
Now imagine the amount of time it would take to perform the following process:
- Open the article
- Compress each image
- Resize or reposition each image
Let’s say it takes me 20 seconds per image (I wish!).
With 4,000 images times 20 seconds = 1,320 minutes or 22 hours.
Ain’t nobody got time for that!
We want a plugin to do the manual tasks for us.
What we want
- Less than 5-click setup
- Bulk compression of existing images
- Automatically compress new images
2. Compression Type
Compression Type = the method used to reduce the file size and maintain the quality of the image.
There are two ways you can compress images:
- Lossy compression
- Lossless compression
Lossy compression gives you a much smaller file size, but this also reduces the quality of the image.
It works by removing data from the original file to reduce the amount of disk space the it takes up. Often, this leaves a very small file size but removing data from the file can leave images pixelated.
Lossless compression also gives you a smaller file size, but it does not reduce the quality of the image.
This is because lossless compression does not remove any data from the file. Instead, it rewrites the file in a more efficient manner so it doesn’t take up as much space.
If you were to take the same file and compress it using each method, you would get these results:
- The lossy file would be smaller than the lossless file
- The lossless file would be sharper/ higher quality than the lossy file
- Both files would be smaller in size than the original image
Whatever method you choose, there is a file size vs quality compromise to be made
Personally, I don’t like the idea of losing quality, so I typically go for a plugin that allows me to use lossless compression.
But there can be instances where there are lots of large images in a post and the quality isn’t all that important (think Buzzfeed style list posts or this from Rolling Stone).
So, I’m hedging my bets and looking for a plugin that will allow me to use both compression methods.
What we want
- Option to use lossy and lossless compression
3. File Types
File Types = the format of the files that the plugin is capable of compressing.
The most popular image types on the web are PNG and JPG.
Any plugin we use must be able to compress both of these image types.
GIFs and animated GIFs are also pretty popular. Ideally, the plugin would also be able to compress these as well.
What we want
4. Constrain Size of Images
Constraints on image size = a pre-set, maximum image size so that any files over that size are automatically compressed or rejected.
Some people are guilty of putting huge images in blog posts (**cough**Perrin**cough**).
Images are great to break up text or show off a product. But they can cause the page to load very slowly. Lager images take longer to load.
The plugin we choose would ideally be able to set limits on the size of the image in terms of width and height.
More importantly, it should be able to stop your team members from uploading a photo with a file size over a certain limit to prevent issues with load time.
What we want
- A maximum file size for images
- Maximum width and height for images
5. Value for Money
Best value for money does not necessarily mean free — or even cheap.
Best value for money means the tool that does the best job for the best price.
In our view, good tools are worth paying for, and there are a few tools we pay hundreds of dollars of months for (don’t worry; none of these are that expensive). But the point is that if we are going to spend money, we want a high value per dollar.
Best Image Compression Plugins for WordPress
WP Smush is one of the most popular image compressions plugins for WordPress.
It compresses JPG, GIF and PNG images. After initial setup, it will automatically compress the images when you upload them.
The plugin uses lossless compression. This maintains the image quality, but doesn’t reduce image size as significantly as lossy compression.
WP Smush allows you to optimize up to 50 images in bulk. This means you can go back through your existing images in batches within the WordPress library to compress them.
Bulk image compression is a good idea, but this doesn’t go far enough for me. At 4,000 images, this would still mean running 80 batches. I’ve got better things to be doing with my time.
You can, however, set max image sizes, so any images uploaded that are bigger than the specified will be automatically resized.
EWWW Image Optimizer
EWWW Image Optimizer is designed to compress images on WordPress sites using lossless compression.
However, the plugin also provides you with the option to use lossy compression if you’re more concerned with file size.
It ticks another box by automatically optimizing PNG, PDF, JPG and GIF images.
Probably the best thing about EWWW is that it doesn’t have batch limits, so you can optimize all your images going retroactively in one go.
The pro version costs $0.003 per image. So, if you want to optimize 10,000 images is it going to cost you $30. It’s a pretty cost effective solution given that very few people will be optimizing anywhere near that many images per month.
I have found there are two main pricing models while looking at these plugins. They either price by GB or by photo (be that by single image, 100 images or 1,000 images).
I’m inclined to favor plugins that go the per photo route.
It’s just so much easier to understand. I know it will cost me $12 to compress the 4,000 images on Authority Hacker. I can live with that.
While the other plugins may be cheaper, I can’t work it out. So, I’m going to stick with what I understand.
Overall, EWWW does pretty much everything that we are looking for from a plugin at a pretty reasonable price. It is a very good option.
Kraken is another extremely popular plugin for compressing images.
Like EWWW, it gives users the option of lossy or lossless compression techniques to compress JPG, PNG, GIF and animated GIF file formats.
Kraken also optimizes thumbnails to make sure the page loads as quickly as possible and reduce the burden on servers.
Kraken aims to find a balance between file size and image quality. The default setting is intelligent lossy compression.
In their own words:
“Kraken.io’s intelligent lossy image optimization applies a variety of techniques and processing steps to input images to recompress them to a lower quality level which falls below the human perceptible threshold.”
This adds another layer of granularity and seems to have the benefits of each compression method without the drawbacks.
There’s also the option to switch to lossless compression if you wish.
Kraken’s pricing policies are quite complex, though. This puts me off a bit.
The packages start from $5 per month for 500MB of images. If this runs out, every additional GB is a further $5.
What is 500MB? I’ve no idea. It means nothing to me.
A quick Google search tells me it is around 80 high quality photo, but, at this point, I’ve already lost interest.
The second package costs $9 per month. This will get you 2GB of images and the price of each additional GB of images compressed reduces to $4.
This progressive pricing policy continues all the way up to the Enterprise package. It’s not cheap at $79 per month, but this will give you 60GB worth of images each month. After that, it only costs an additional $1 per GB of images.
Imagify is a freemium optimization plugin.
Like most of the plugins, it uses lossless compression by default. However, they categorize their compression into three levels of severity:
- Normal – Lossless compression where the image quality remains the same and the file size reduces slightly.
- Aggressive – Lossy compression where there may be slight loss of quality but the file size becomes even smaller.
- Ultra – Extreme lossy compression where the file size reduces significantly but the quality will also take a substantial hit.
Imagify allows you to compress 250 images per month for free. This is quite reasonable, but if you have an old website and want to optimize images in arrears, this may prove to be an issue.
With the paid versions, you get the option of 1GB, 2GB, 5GB, 15GB or 50GB plans ranging from $4.99 per month, all the way up to $69.99 per month.
Imagify also automatically compresses the images, which means there is no manual action required.
Overall, it can be a good option if you’re not compressing too many images. It does the basics well and gives you a choice over the severity of the compression you are looking for.
Short Pixel Image Optimize
Short Pixel Image Optimizer is another freemium image compression plugin that’s beginning to make a name for itself.
It really covers all the bases with both lossy and lossless optimization, automatic compression and bulk compression.
A drawback of Short Pixel is it doesn’t allow you to automatically set a max image width and height.
It would be nice if the plugin stopped users placing 1,000px+ images in a normal article. Alas, that can’t be done in Short Pixel.
Like other plugins, there is a free plan. Short Pixel allows 100 free images per month rather than the 250 you can get with Imagify.
The price plans are slightly different. I actually prefer the way that Short Pixel have put the pricing plans together. Rather than messing about with GB, Short Pixel will allow you to optimize 5,000 images for $4.99 per month.
If you are anything like me, this is a lot easy to understand.
With the understanding that I’m never going to need 5,000 images compressed per month, I would be quite happy going with that package knowing that I would only ever have to upgrade to a larger package once in a blue moon.
Overall, the price isn’t going to break the bank and it performs almost all of the features that we need it to do. All in all, Short Pixel is a solid option.
How Do They Compare?
|Plugin||Automation||Compression Type||File Types||Automatic Resize||Price|
For each criteria, plugins have been given a score from 0 to 5 (with 0 being the worst and 5 being the best).
If a plugin does not have a feature at all, it will score a zero. If a feature meets the full requirements it will get a 5.
Anywhere in between will get a score on the sliding scale depending upon how close it gets to what we require.
For example, for ‘Compression Type:
- Kraken gets 5 because it has both lossy and lossless compression
- WP Smush gets 2 because it does not have lossy compression
What One Should You Use?
To be honest, these are five really good image compression plugins. I would be happy to have any of them on my site.
If I just wanted to compress images to keep things ticking over I would use WP Smush. It uses lossless compression, so you will retain the picture quality and it will slightly reduce the image size. It has all the features other than lossy compression and, as an added bonus it is free.
However, if the site was image heavy and there were some places where you could get away with a lower image quality, I would use Short Pixel.
It does everything other than automatically resize images and I like the way they have structured their pricing plans.
Having said that, if I knew I was going to need to optimize more than 100 images but less than 250 per month, use Imagify as it is free at that point.
As I mentioned, these are all good plugins. Another thing to remember is that image compression isn’t rocket science. You just need something that will get the job done. All of these plugins will do that to an acceptable standard.