10 Best Image Optimization Tools

Large images can slow a website and make uploads inconvenient, but aggressive compression can leave photos looking rough. This guide covers simple browser tools, desktop apps, and services that fit into a publishing workflow.

Keep an original copy before converting or batch-processing files. The best setting depends on the image: a photograph, logo, and transparent illustration do not need the same format or compression level.

Quick picks

• Best for hands-on control: Squoosh — compare formats and quality visually.
• Best for quick batches: TinyPNG — a simple browser workflow for common image files.
• Best for Mac: ImageOptim — drag-and-drop desktop compression.
• Best for websites: Cloudinary — transform and deliver images through a media platform.

How we picked

We chose tools with distinct approaches, from local desktop compression to hosted image delivery. Before choosing, consider:

• Privacy: whether files are processed locally or uploaded.
• Workflow: single images, batches, or automatic site delivery.
• Output: support for formats and transparency your project needs.
• Control: ability to balance file size against visible quality.

Browser-based compression

1. Squoosh

Squoosh runs in the browser and lets you compare codecs and compression settings with a visual preview. That side-by-side control is excellent when you need to preserve detail in a product photo while reducing its file size. It is less convenient for a large unattended batch than an automated pipeline, and settings still need human judgement. It is free.

Best for: designers choosing a format and quality level for a few important images.

2. TinyPNG

TinyPNG compresses PNG, JPEG, and WebP images through a simple upload-and-download page, with options also available for developer workflows. Its quick interface suits someone preparing a handful of graphics before adding them to a site. Free use has limits, and uploading confidential artwork may not suit every organisation. It has a free plan with paid upgrades.

Best for: bloggers and small shops who need quick compression without installing software.

3. Compressor.io

Compressor.io provides browser-based compression for common image formats, with lossy and lossless options depending on the file type. It is useful for a one-off asset when installing an app would be unnecessary. The selection of settings is less extensive than a dedicated editing workflow, and online processing means you should consider file privacy. It has free use with paid upgrades.

Best for: occasional users reducing images before attaching or publishing them.

4. Optimizilla

Optimizilla lets users compress several JPEG or PNG files and adjust quality while previewing the result. The preview helps reveal when a smaller file begins to show distracting artefacts. It focuses on a narrow set of formats and does not provide a full image editing or delivery system. It is free.

Best for: people preparing a small group of JPEGs or PNGs with visual checks.

Desktop and publishing workflows

5. ImageOptim

ImageOptim is a Mac app that compresses images by dropping unnecessary metadata and optimising file encoding. Dragging files into the app fits naturally into a designer's export routine, and local processing can be preferable for private assets. It is a Mac-focused desktop option rather than a cross-platform cloud service. It is free.

Best for: Mac designers cleaning up exported images before handing them to a developer.

6. ShortPixel

ShortPixel offers image compression and WordPress-oriented optimisation, including conversion and delivery options depending on the plan and setup. A site owner can reduce existing media as well as images added later, avoiding a manual trip through each file. Usage limits and configuration choices need attention, particularly on large libraries. It has a free plan with paid upgrades.

Best for: WordPress publishers automating optimisation for a growing media library.

7. Imagify

Imagify provides image optimisation with WordPress integration and compression modes that trade file size against fidelity. Its connection to a publishing workflow can be more convenient than processing each upload by hand. Results depend on chosen settings, and high-volume sites should check the current plan allowances before migrating a large library. It has a free plan with paid upgrades.

Best for: WordPress site owners who want compression built into their publishing routine.

8. EWWW Image Optimizer

EWWW Image Optimizer is a WordPress plugin focused on optimising images within a site workflow, with features varying between local and cloud processing options. It can help administrators handle existing media and new uploads from the same dashboard. Setup choices are more involved than a simple browser compressor, and administrators should understand where processing occurs. It has a free plan with paid upgrades.

Best for: WordPress administrators who want to manage optimisation from their own site dashboard.

Delivery and advanced control

9. Cloudinary

Cloudinary is a media platform that stores, transforms, and delivers images and video, including on-the-fly resizing and format choices. Developers can generate variants for different screen sizes rather than maintaining every rendition manually. It introduces a service and configuration layer, so it may be excessive for a small static site. It has a free plan with paid upgrades.

Best for: development teams serving image-heavy sites or applications at multiple sizes.

10. Kraken.io

Kraken.io offers image optimisation through a web interface and developer integrations for automated workflows. It is useful when a team wants compression to fit into a repeatable asset process instead of depending on someone remembering to optimise files. Integration work and plan limits matter, and a simple manual tool may be enough for a small number of images. It has a free trial and paid plans.

Best for: developers automating image compression in a production workflow.

How to choose the right one

If you only publish a few images, start with a browser compressor and inspect the result at its actual display size. For a Mac-based design handoff, a local app may be quicker; for WordPress, a plugin can prevent unoptimised uploads from accumulating. Larger sites often benefit from responsive image delivery, where visitors receive a size suited to their screen rather than a full-resolution original.

Use Stockio's image resizer calculator to work out suitable dimensions before exporting. Keep accessible, descriptive alternative text separate from compression, and check the page on a phone as well as a desktop. For site speed measurement, use a report from PageSpeed Insights after changing images. Browse Stockio resources for other useful design resources and design tools when building an asset workflow.

Key takeaways

• Preserve originals before batch conversion or compression.
• Choose formats and settings based on the image's content and transparency.
• Local processing and online uploads have different privacy implications.
• CMS plugins help prevent future uploads from undoing optimisation work.
• Check page performance after resizing; smaller files are not the only factor.