What is the insert_img_dimensions filter?

insert_img_dimensions is an alternate spelling of insert_image_dimensions that the module accepts. Both names enable the same filter.

Is insert_img_dimensions enabled by default?

No. insert_img_dimensions is not in CoreFilters, the default RewriteLevel; it runs only when you enable it by name with EnableFilters.

How do I enable insert_img_dimensions on Apache and nginx?

Add ModPagespeedEnableFilters insert_img_dimensions on Apache or pagespeed EnableFilters insert_img_dimensions; on nginx. On IIS, add pagespeed EnableFilters insert_img_dimensions to pagespeed.config.

filter · Image filters

Insert image dimensions (insert_img_dimensions)

Category:: Image
CoreFilters:: No
OptimizeForBandwidth:: No
Risk:: Generally safe

insert_image_dimensions adds explicit width and height attributes to <img> tags that lack them. This prevents layout shifts (CLS) but does not resize the image file itself. insert_img_dimensions is an accepted alternate spelling of the same filter.

When to use it

An alternate spelling of insert_image_dimensions: the module accepts both names for the same filter.
Not in CoreFilters: it runs only when you enable it by name.
Risk rating on these docs: Generally safe.

Risks

The Image filters page lists no specific risks for this filter. If a page misbehaves with it, DisableFilters insert_img_dimensions turns it off for the scope you set it in.

Configuration

Enable it in the module configuration, at server, virtual-host or location scope:

Apache

ModPagespeedEnableFilters insert_img_dimensions

nginx

pagespeed EnableFilters insert_img_dimensions;

IIS (pagespeed.config)

pagespeed EnableFilters insert_img_dimensions

Parameter	Default	Description
`ImageLimitResizeAreaPercent`	100	Only resize if the result is this percentage of the original area or less

Scoping, ForbidFilters and the thresholds filters read: Choosing filters.

Frequently asked questions

What is the insert_img_dimensions filter?: insert_img_dimensions is an alternate spelling of insert_image_dimensions that the module accepts. Both names enable the same filter.
Is insert_img_dimensions enabled by default?: No. insert_img_dimensions is not in CoreFilters, the default RewriteLevel; it runs only when you enable it by name with EnableFilters.
How do I enable insert_img_dimensions on Apache and nginx?: Add ModPagespeedEnableFilters insert_img_dimensions on Apache or pagespeed EnableFilters insert_img_dimensions; on nginx. On IIS, add pagespeed EnableFilters insert_img_dimensions to pagespeed.config.

insert_image_dimensions — Insert image dimensions
resize_images — Resize images
resize_rendered_image_dimensions — Resize to rendered dimensions
convert_gif_to_png — Convert GIF to PNG
convert_jpeg_to_avif — Convert JPEG to AVIF
convert_jpeg_to_progressive — Progressive JPEG
convert_jpeg_to_webp — Convert JPEG to WebP
convert_png_to_jpeg — Convert PNG to JPEG

This page is drawn from the insert_img_dimensions entry on Image filters. Every filter in one table: PageSpeed filters.