Optimise WordPress images: The complete guide and the best plugins 2026

You’ve just uploaded a great photo, but your website feels like it’s taking forever to load? You’re not alone. Non-optimised images are one of the most common performance killers on WordPress websites. The good news is that the problem can be solved quickly and easily with the right plugin, without any prior technical knowledge.

The most important facts in brief

• Images often make up more than half of a website’s data volume. If they are not optimised, the loading time suffers and so does your Google ranking.
• The right plugin takes care of the optimisation fully automatically in the background. No manual editing, no prior technical knowledge required.
• It all comes down to three features: WebP conversion, automatic compression during upload and a bulk optimiser for existing images.
• We have tested and compared 10 plugins. For Raidboxes users, FastPixel is the strongest combination of image optimisation and caching.

What are WordPress plugins for image editing and optimisation?

WordPress plugins are extensions that can be integrated into the content management system (CMS) and have been specially developed for use within WordPress. They enable all users to edit, optimise and manage images within the CMS.

Other image editing programmes, such as Adobe Photoshop, Figma or GIMP, are separate applications that can be installed on the user’s computer and used independently of a CMS.

These programmes usually offer a more extensive range of editing functions and tools. However, inexperienced users require a significantly longer familiarisation period and the application is often more complicated than with WordPress plugins.

What problems arise if you don’t optimise images?

Unoptimised images slow down your website, damage your Google ranking and cause visitors to bounce before the page has even loaded.

Here’s a quick overview of the most common problems and why they affect your success:

1. Longer loading times: Large image files slow down your entire website. A delay of just a few seconds can cause visitors to bounce before the page has even loaded.
2. Higher data consumption: This is a particular problem for users with a mobile connection. Unoptimised photos consume an unnecessary amount of data. This is a deterrent.
3. Poorer SEO: Search engines such as Google measure the loading time and take it into account when ranking. If you slip up here, you will lose visible rankings in the search results.
4. Poorer user experience: A sluggish website does not leave a good first impression. The likelihood of visitors returning or recommending the site to others decreases significantly.
5. Wasted server resources: Unoptimised images take up more storage space and computing power on the server. This costs unnecessary resources and can affect the overall website performance.

How can I compress and optimise WordPress images?

The simplest and most effective method: use a WordPress plugin for image optimisation. These plugins take care of compression, scaling and conversion automatically. You upload your images as usual and the plugin does the rest in the background.

There are basically two approaches:

• Automatic optimisation during upload: The plugin intervenes directly when uploading and optimises every new image immediately.
• Bulk Optimizer: You optimise all existing images in the media library at once. Practical if you are updating an existing website.

Most good image optimisation plugins combine both.

Optimise WordPress images: The 10 best plugins in comparison

Here we present ten of the best plugins, with clear strengths, weaknesses and recommendations for whom they are best suited.

1. fastPixel

FastPixel is a performance plugin that combines image optimisation with caching. It automatically handles image compression, delivers images in the modern WebP format and is directly integrated into the Raidboxes infrastructure, which makes setup particularly straightforward.

The plugin works completely in the background: no manual configuration, no separate setup. Images are automatically optimised, scaled and delivered in the correct format. If you host on Raidboxes, you can activate it directly via the dashboard.

Best suited for: Raidboxes users and anyone who wants to combine image optimisation and caching in one plugin.

2. smush

Smush is one of the best-known and most widely used image optimisation plugins for WordPress. It automatically compresses images during upload without any visible loss of quality and supports JPEG, PNG and GIF. Particularly practical: the integrated bulk optimiser, with which you can optimise all images already uploaded in the media library at once.

The free version is perfectly adequate for many websites and already supports WebP conversion. If you want to optimise larger images, use CDN delivery or need unlimited bulk optimisation, you should use the Pro version.

Best suited for: Beginners, small websites and anyone looking for a simple, free solution.

3. shortPixel

ShortPixel is one of the most powerful plugins when it comes to real savings in file size. It offers three compression levels (lossless, lossy, glossy) and automatically converts images to WebP format. The Bulk Optimiser is also sophisticated: you can process thousands of images at once.

ShortPixel is a particularly strong choice for agencies and freelancers who manage many websites with large media libraries. Billing is based on API credits, which is flexible and cost-effective for large projects.

Best suited for: Agencies, freelancers and anyone with lots of images or high image quality requirements.

4. EWWW Image Optimiser

EWWW Image Optimizer is a versatile plugin that optimises JPEG, PNG and GIF files. A special feature: Image optimisation can be carried out either locally on your server or in the cloud, which gives you flexibility in terms of performance.

The plugin works reliably in the background and also offers a bulk optimiser for existing images. The settings are somewhat more extensive than with Smush, which users with some experience will appreciate.

Best suited for: Users with some technical background who want full control over compression.

5. imagine

Imagify comes from the same team as WP Rocket. The plugin is intuitive to use, offers three compression levels and automatically converts images to WebP format. Particularly good: the clear presentation of the savings achieved directly in the dashboard.

If you already use WP Rocket for caching, you will benefit from the seamless integration of both plugins. Imagify is quick to set up and requires hardly any work on a day-to-day basis. If you want to reduce the size of WordPress images without having to do it yourself, this is the right choice.

Best suited for: WP Rocket users and anyone who values simplicity and a clean interface.

6. imsanity

Imsanity solves a common problem: images are uploaded directly from the camera, often several megabytes in size, even though the website never displays them in full resolution. Imsanity automatically sets a maximum upload size and scales down images that exceed this limit directly during upload.

The plugin can be configured separately for different image types and supports conversion to JPG format.

Best suited for: Websites with several editors or customers who upload images themselves.

7 TinyPNG

TinyPNG delivers very good compression results. It supports JPEG, PNG and WebP and can also automatically convert images to WebP or AVIF format. It is easy to use: new images are automatically optimised when uploaded and existing images can be processed using the Bulk Optimizer.

The free version allows 500 compressions per month, which is easily sufficient for many smaller websites.

Best suited for: Websites with many PNG files or anyone who already knows and appreciates TinyPNG.

8. optimus

Optimus is a lean plugin that focusses on lossless image compression and is especially designed for data protection. The optimisation runs on servers in Germany and images are deleted immediately after processing. This is a clear plus point for GDPR-conscious users. However, WebP conversion is only available in the paid HQ version.

Best suited for: Users with a focus on data protection and GDPR compliance.

9. regenerate thumbnails

Regenerate Thumbnails solves a specific problem: If you change the theme of your WordPress website or change the thumbnail sizes in the settings, the existing thumbnails often no longer fit. This plugin regenerates all thumbnails, either individually or for the entire media library at once.

It is not a classic image optimisation plugin, but an indispensable tool when changing themes or after design adjustments.

Best suited for: Anyone who has changed their WordPress theme or customised thumbnail sizes.

10. image watermark

Image Watermark fulfils a different purpose: it protects your images from unauthorised use by automatically adding a watermark, either as text or as an image overlay. You can customise the position, transparency, font and font size and apply the watermark to different image types separately.

The plugin can also be applied retroactively to images that have already been uploaded. Practical if you want to protect an existing media library.

Best suited for: Photographers, designers and anyone who wants to protect their images from unauthorised use.

Optimise images for your website: Tips that really make a difference

A good plugin is the first step. With these additional tips, you can get even more performance out of your images:

Use WebP format: WebP images are on average 25-35% smaller than JPEG or PNG, with comparable image quality. All modern browsers support the WebP format. Use it if your plugin offers it.

Scale images before uploading: Do not upload photos directly from the camera. A 6000 x 4000 pixel image will never be displayed in this resolution on a website. Scale them to the maximum display width before uploading. This saves an enormous amount of storage space.

Activate lazy loading: Images that are located below the visible area are only loaded when users scroll there. WordPress has integrated lazy loading natively since version 5.5. Make sure it is active for you.

Don’t forget alt texts: Alt texts not only improve accessibility, but also help search engines to understand the content of your images. This is a simple but effective SEO lever.

Regular optimisation: If you regularly publish new content, make sure that automatic optimisation is active when uploading. This saves you manual work and ensures that all new images are optimised immediately.

SEO-optimise images on the website with AI: The Raidboxes AI Assistant

If you want to set up your WordPress website from scratch, you can use the Raidboxes AI Site Assistant. It automatically creates the design, layout, texts and page structure and installs the appropriate plugins directly on request. This means you can build a high-performance website right from the start without having to manually configure every detail.

In combination with FastPixel, image optimisation is covered right from the start. The AI Site Assistant takes care of the set-up, FastPixel takes care of the images. This saves you time right from the start and you no longer have to worry about image optimisation separately.

Conclusion: A fast WordPress website with the right plugins

Image optimisation is one of the simplest and most effective measures to improve the loading time of your WordPress website and thus also your SEO rankings and the experience of your visitors.

Choosing the right plugin depends on your requirements:

• Looking for a simple, free solution? Smush is a solid start.
• Do you manage many websites with large media libraries? ShortPixel convinces with strong compression and flexible prices.
• Do you have multiple authors? Imsanity automatically prevents huge uploads.
• Do you host on Raidboxes? Then FastPixel is our clear recommendation. It combines image optimisation and caching in one plugin, is directly integrated and makes the whole process a breeze. Once you have activated FastPixel, you no longer need to worry about image optimisation.

In the end, the best plugin is the one you really use. Start with one, activate automatic optimisation and your website will thank you for it.

Frequently asked questions (FAQ) about reducing the size of WordPress images