Image optimization can be annoying at so many levels: it’s a pricy and time-consuming task that requires know-how. Keep reading and get not only the needed know-how in just a minute but also an introduction to the most popular image optimization plugins and the one that is really worth giving it a try.
Image Optimization Methods
There’re two way to optimize images: via lossless and lossy compression.
Lossless compression is the preferred image optimization method, especially in cases where photos are of great importance for site visitors’ experience. The reason is that it doesn’t lead to loss of image quality. This, however, means also that file size is only reduced with an average of 10-30 %, depending on file type (.png, .jpg, etc.).
Lossy compression, on the other hand, reduces the number of color nuances in a picture, thus leading to much bigger savings, up to 50-90% in some cases. Additionally, you can choose whether meta data should be deleted to achieve even bigger reduction of file size.
Even though people say that one can’t really see the difference in image quality caused by lossy compression and even though page load times benefit a lot from the notable reduction in file size, it’s not always recommended to use this method for image optimization.
The rule of thumb is that images that aren’t that sensitive to compression (due for example very high quality or limited colors/details) can and should be optimized using lossy compression. For the rest of the images applies the opposite.
If you, however, aren’t sure which method you should use, you can for the most of it use lossless compression to begin with, check the result with a service as GTMetrix, and if a warning appears regarding image optimization of the particular item, re-optimize using lossy compression.
Note! The fact that one or a few media files trigger a warning should be weighed against the gain in terms of better user experience. For the most part of it, optimization is considered successful when it helps to achieve better performance without affecting negatively user experience. Going after 100 % image optimization just for the sake of performance scores isn’t rentable.
When it comes to image optimization methods, you can not only choose between lossy and lossless compression but also between on-site optimization, cloud solutions, manual, and buck optimization.
On-site image optimization means that you install a plugin and your galleries get compresses directly within your WordPress directory, usually a back-up directory for the original images is also created.
Cloud solutions require that you create an account and upload every image to the cloud – or send it in via a plugin – to afterwards download its optimized version.
Manual compression means that you have to work with each image individually, by for example uploading it to the cloud or clicking on an optimization button.
Bulk options allow you to optimize all your images with just one click after setting your compression preferences. Needless to say, this is the one option owners of bigger sites or galleries can’t manage without.
The Most Popular Image Optimization Plugins
If you’ve looked after an image optimization plugin for a while, you know that there’re a few quite popular ones that you simply can’t avoid stumbling into: EWWW Image Optimizer, WP Smush, TinyPNG, and Kraken Image Optimizer.
Why they’re the most popular ones, I can’t say. Maybe it’s just a question of marketing. But let’s look closer at them – and compare to yet another, a bit less known plugin (which is definitely worth your attention).
EWWW Image Optimizer
EWWW Image Optimizer is quite nice as it offers both a free plugin version and a paid cloud version, allowing you to choose what fits you best.
You can choose between lossy and lossless compression as well as manual and bulk image optimization. There’re no limits in relation to image size and number of pictures you optimize in the plugin version, making it completely free to use.
It provides you with exhaustive controls making it easy to adjust the process. Even if you don’t understand all options in the beginning, you can experiment and figure out what works best for you.
The only – but serious – downside of this plugin is that it requires access to server management as the plugin needs certain permissions in order to install files and work. With shared hosting you’ll often find out that you don’t have the needed permissions and you’ll depend on the willingness of your provider to enable them.
If they refuse, you simply can’t use the plugin.
If you manage your server yourself, it’s more or less a simple task to configure the plugin.
If you choose to use the cloud version, it costs 0.005 USD per optimized image.
While I like EWWW Image Optimizer, I don’t recommend using WP Smush. The free version of the plugin is quite useless in that it only optimizes small images, limits you to optimizing 50 images in bulk mode, and optimizes extremely little (not enough).
Furthermore, you can’t choose to optimize lossy.
The paid version of the plugin still limits the size of images that can be optimized to up to 32 MB (nobody knows why) and costs 49 USD/month.
Even if you want to pay the price, you can use your money better than that.
It does though, from time to time, underperform, meaning that site performance tests detect some images as not optimized and you can unfortunately not do anything about it. This is, however, an issue you’ll face with most plugins.
You can control the max size of optimized images (resize at upload) but be aware that you can’t control the type of compression. The plugin processes pictures exclusively lossy. Likewise, there aren’t any automated options for optimizing images that aren’t uploaded via the media library.
Last but not least, there’s a limit for monthly optimizations: 500 images. When you surpass this limit, you have to pay 0.009 USD/image.
Kraken Image Optimizer
Kraken Image Optimizer is the only compression tool that doesn’t offer any free resources, if you don’t count the free trial providing you with the option to test the service by optimizing 100 MB worth of images. The price afterwards begins from 5 USD/month for 500 MB.
Via the plugin images are pulled from your installation, optimized in the cloud, and re-downloaded. You can use functions as manual and bulk optimization and you can set max size for uploads.
You can also choose to remove or preserve meta data in order to achieve further reduction of file size.
Even though the plugin offers an okay service, it doesn’t offer something so exceptional that makes it worth it to pay for, especially given that there are enough other image optimization plugins out there that perform just as well and give small site owners the opportunity to do everything for free.
ShortPixel is a great image optimization plugin. It offers not only manual and bulk processing but also re-optimization and restoration of the original image.
You can choose between lossy, glossy, and lossless compression in connection to bulk, manual or automatic processing. You can also re-optimize images, meaning that an image that was optimized using lossy compression can be re-done using lossless instead – and the other way around. This function is quite nice if you aren’t sure which method to use.
The fact that all originals are saved (if you choose to save them) solves once and for all the problem with images being ruined by optimization plugins. ShortPixel features a one-click original restoration option.
The plugin optimizes both images and thumbnails and there’re no image size restrictions. A quite nice feature is that you can optimize all popular image formats, including pdf.
Additionally, the plugin creates a WebP version of images and exchanges the standard <img> tag in your pages’ code with the <picture> tag, allowing you to list a number of different formats to serve to browsers. This is necessary, as, even though WebP offers without a doubt the best compression, there are stil many browsers that don’t support it.
You can optimize 100 images a month for free and if that’s not enough for you, you can choose between monthly payments (starting at 4.99 USD for 5000 images) or one-time payments (starting at 9.99 USD for 10000 images). Creation of WebP versions of images doesn’t use up additional credits.
The Best Image Optimization Plugin
As you noticed, all image optimization plugins offer more or less the same. Differences are found primarily in pricing, user control, and optimization type.
However, the winner plugin in this review has to offer a little bit more than other plugins:
- Ease of use: no complicated installation or setup as for example with EWWW Image Optimizer (which otherwise was a favorite to win).
- Lossy AND lossless compression: TinyPNG would otherwise have won the first place here if they didn’t only offer lossy optimization.
- WebP: It can be expected that more plugins will include WebP in their options in the future. However, as of 2017, there are still only a very few out there offering such a feature.
- Controls: as no other plugin, it offers re-optimizations and restoration of originals only with a simple click.
- Price: the price (after running out of free monthly quota) is quite reasonable and five times lower than what the next-best competitor offers: 0.001 UDS/image.
You’ve probably already figured it out. The winner of this review is without a doubt ShortPixel. If you’re still not convinced, you have now the chance to test it and save even more by enjoying 50 % more credits upon subscription or with your one-time payment (the link gives you 150 free images to start out with instead of 100).
Disclaimer: WPBloggingNerd uses ShortPixel at the moment of writing this post at our own expense. The link giving you 50 % more image optimization credits is provided in cooperation with ShortPixel’s developers only for your benefit. WPBloggingNerd doesn’t benefit in any way of you using this offer.