Is Astro making images larger?

[blopker]

Astro Info

Astro                    v4.16.7
Node                     v23.0.0
System                   macOS (arm64)
Package Manager          bun
Output                   static
Adapter                  none
Integrations             @astrojs/mdx
                         @astrojs/tailwind
                         pagefind
                         @astrojs/solid-js
                         astro-icon

If this issue only occurs in one browser, which browser is a problem?

No response

Describe the Bug

It seems like the image optimization process is actually making image larger. Here's the output from astro build:

4:34:25 PM:  generating optimized images 
4:34:25 PM: 09:34:25   ▶ /_astro/bali_vids.Bokn6UPM_ZdW7qj.webp (before: 92kB, after: 106kB) (+280ms) (1/29)
4:34:25 PM: 09:34:25   ▶ /_astro/traffic.CY3uXBQB_Z2coWA1.webp (before: 70kB, after: 82kB) (+114ms) (2/29)
4:34:25 PM: 09:34:25   ▶ /_astro/fastboat.Bv4mBUji_2hYwmC.webp (before: 80kB, after: 93kB) (+134ms) (3/29)
4:34:26 PM: 09:34:26   ▶ /_astro/horsey.BXViqSaB_9Am1W.webp (before: 97kB, after: 112kB) (+229ms) (4/29)
4:34:26 PM: 09:34:26   ▶ /_astro/ubud.CvSjUs1F_1clYMi.webp (before: 153kB, after: 180kB) (+294ms) (5/29)
4:34:26 PM: 09:34:26   ▶ /_astro/lush.PzJLZ22N_2kV5sa.webp (before: 116kB, after: 135kB) (+120ms) (6/29)
4:34:26 PM: 09:34:26   ▶ /_astro/sunset.xi1IdWl6_15L7mX.webp (before: 54kB, after: 63kB) (+244ms) (7/29)
4:34:27 PM: 09:34:27   ▶ /_astro/tr-header.DAh8LYlv_1ty9jI.webp (before: 173kB, after: 201kB) (+299ms) 
[truncated]

Collectively, Astro is adding 541 kB to the images for this site. Is this expected?

Here's the output for ls for a single image, first one is the original and second is the post processed image in dist/_astro:

116K Oct 27 16:19 lush.webp
135K Oct 27 16:31 lush.PzJLZ22N_2kV5sa.webp

Is it possible for Astro to throw away the optimization if the original image is smaller than the processed image?

What's the expected result?

Astro should not be making images larger.

Here's an example image that is made larger:
lush.webp.zip

Link to Minimal Reproducible Example

None

Participation

• I am willing to submit a pull request for this issue.

[github-actions]

Hello @blopker. Please provide a minimal reproduction using a GitHub repository or StackBlitz. Issues marked with needs repro will be closed if they have no activity within 3 days.

[Princesseuh]

Astro can when the images are already optimized, as it uses pretty safe Sharp settings to ensure the builds don't take too long / compatibility.

Unfortunately, it's not possible to make it so Astro does not use the image if the generated one is larger, perhaps the fix here is to allow users to configure Sharp more.

[blopker]

I see. I did go through the image processing pipeline a bit and yeah, it seems like adding a check for the file size would be tricky. It would only really make sense if no other transformations happened anyway (rotations and such).

I'm just going to use passthroughImageService to disable optimizations since I use https://github.com/blopker/alic for everything already.

I'm all for exposing some more configuration options though! If Sharp can get to level of optimizations Alic can, I'd prefer to use that.