AI MediaBoost image editing: what it does and how to use it – THRON Guide

With the AI MediaBoost image editing feature, you optimize each image directly in the delivery URL: crop, resize, adjust brightness and format without creating and storing variants in advance. The engine generates the requested version on the fly and automatically caches it for subsequent requests.

The order of operations is always fixed, regardless of how you write parameters in the URL:

Crop: cropping the original image
Resize: resizing the resulting image
Modify: visual adjustments without altering pixel dimensions

Resize the image

Use resize parameters to define output image dimensions. The original aspect ratio is always preserved: if you specify both width and height with different proportions from the original, the more restrictive measurement is applied and the other is ignored.

Parameter	Type	Default	Description
`w`	int	original width	Desired width in pixels.
`h`	int	original height	Desired height in pixels.
`zoom`	boolean	none	Allows enlargement beyond original dimensions. Requires both `w` and `h`.
`dpr`	int	none	Device Pixel Ratio. Values: `1`, `2`, `3`, `4`. Multiplies requested dimensions for high-density screens.

Examples:

w=320: width 320px, proportional height
w=300&h=300: on a 16:9 image the result is 300×169px (the more restrictive dimension wins)
dpr=2&h=216: height 216px at double density for Retina screens
zoom=true&w=2500&h=2000: enlargement beyond original dimensions (both dimensions required)

Recommended configuration for Retina screens
Use dpr=2 along with w or h. Example: dpr=2&h=216 returns a high-density image without manually doubling dimensions.

Crop the image

Manual cropping allows you to precisely select the image area to preserve. The coordinate system origin is (0,0) in the top-left corner, with the x-axis extending to the right and the y-axis extending downwards. The resulting image aspect ratio may differ from the original depending on the chosen values.

Parameter	Type	Default	Description
`cx`	int	0	Position of the left edge of the crop area (distance from origin on the x-axis).
`cy`	int	0	Position of the top edge of the crop area (distance from origin on the y-axis).
`cw`	int	width − cx	Width of the crop area starting from (cx, cy).
`ch`	int	height − cy	Height of the crop area starting from (cx, cy).

Example: cx=384&cw=1056&cy=54&ch=940, crop from corner (384, 54) with a 1056×940px area.

Absolute pixel values only. Crop parameters do not accept percentage values.

Automatic crop

The crop parameter combines cropping and resizing automatically, eliminating the need to calculate coordinates manually. It ignores all manual crop parameters (cx, cy, cw, ch): do not combine them in the same URL.

Mode	How it works	Ideal for
`crop=centered`	Crops to the center to obtain exactly the dimensions requested with `w` and `h`. Outer portions are removed.	Uniform thumbnails, editorial grids.
`crop=auto`	Analyzes the image and identifies the subject's center of gravity. If you specify both `w` and `h`: adapts the crop to the requested aspect ratio. If you specify only one dimension: crops to the subject area and resizes. If you specify neither dimension: the crop matches the subject area without resizing.	Editorial images, banners, portraits.
`crop=product`	Detects and removes borders with solid color (e.g. white background). If you specify `w` and `h`: adds bands in the detected background color to respect the aspect ratio (or the color defined with `fillColor`).	Product photos on uniform backgrounds, e-commerce.

Recommended configuration for product images (e-commerce)
crop=product&w=600&h=600 automatically removes white borders and returns a ready-to-use square image. Add fillColor=#FFFFFF to enforce white as the fill color (only on images already without background).

Recommended configuration for editorial banners
crop=auto&w=1200&h=630 automatically centers the subject into standard social and banner dimensions, without manual cropping.

Modify image appearance

Modify operations alter visual appearance without changing pixel dimensions. They are always applied after crop and resize.

Quality and format

Parameter	Type	Default	Description
`q`	int	none	Compression quality for JPEG and WebP (range: 5-95). Ignored for PNG.
`q_auto`	string	none	Automatically optimized quality. Values: `highest`, `high`, `medium`, `low`. Preferred over `q` for web delivery.
`format`	string	avif	Output format. THRON automatically selects the best format for the browser; use this parameter only if you have specific requirements and want to choose a specific format. Combine it with the `download=true` parameter to download the image in a specific format.

Recommended configuration for web delivery
Use q_auto=medium: reduces image weight while maintaining good visual quality. The format is already managed automatically by THRON (default: AVIF).

Visual adjustments

All parameters have a range of −100 / +100, default 0 (no effect). Exception: blur, range 0-100.

Parameter	Description
`brightness`	Image brightness (-100, 100)
`contrast`	Image contrast (-100, 100)
`sharpness`	Image sharpness (-100, 100)
`saturation`	Color saturation (-100, 100)
`blur`	Blur (0-100)

Example: brightness=-20&contrast=20&sharpness=30, reduced brightness, increased contrast and sharpness.

Transparency fill

Parameter	Type	Description
`fillColor`	string (HEX)	Color in HEX format (e.g. `#FFFFFF`). Replaces transparency or fills added bands from `crop=product` or `zoom=true`. Only works on images that already have an alpha channel (background already removed): produces no effect on images with opaque background.

## Additional articles
- Guide to Creating and Configuring a Custom Application
- The pKey: What it is and how to manage it

Need help?

For technical issues, contact support@thron.com.

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