Knowledge
How Spark Media Optimizer handles your media
From installation to batch-run: how the plugin integrates into an existing WordPress site.
Installation
Activate the plugin, link your license and choose a compression profile.
Steps
- Scan media library
- Optimize in the background
- Serve modern format
What happens technically with each image
Detection
As soon as an image lands in your media library, Spark recognizes its file type and characteristics, such as format and current file size.
Source file analysis
The plugin determines which approach suits this specific file: a photo with lots of detail requires different considerations than a logo with flat colors.
Compression and/or conversion
Based on your chosen profile, the file is compressed and, where appropriate, converted to a more modern format such as WebP or AVIF.
Secure storage of the result
The result is stored as a copy, with attention to reversibility, so your original doesn't disappear.
Delivery of the right format to the visitor
When visitors come to your site, their browser receives the format it supports, with an appropriate fallback for older browsers.
Settings you control yourself
Spark Media Optimizer works in the background, but you make some choices yourself:
| Setting | What it does | Think about |
|---|---|---|
| Compression profile (lossless / glossy / lossy) | Determines the balance between file size and image quality. | Lossless for no visible loss, lossy for maximum savings, glossy as a middle ground. |
| Target format (AVIF / WebP / original as fallback) | Determines which format is sent to the visitor's browser. | A fallback to WebP or the original keeps the site working for older browsers. |
| Processing scope | Determines whether only new uploads, the existing library, or both are processed. | Useful for migrating in phases instead of processing everything at once. |
What Spark won't do
- No unsolicited deletion of your original files.
- No synchronous processing that keeps visitors to your site waiting.
- No changes to content outside your media library.
- No imposing a fixed format if you set a different target format yourself.
Frequently asked questions
In the background, in a queue. That way, a visitor doesn't have to wait for an image to finish processing.
Spark can include them, but double optimization usually provides little additional benefit. Compare the result in bytes and quality before doing that structurally.
Yes, you set up a profile that matches your site; see the plugin settings page for the exact options.
Spark works with safe copies and takes rollback into account, so if you're unsure, you can always go back to the original state.
Processing focuses on files in your WordPress media library. Images loaded from outside usually fall outside of this.