# Ghost - properly size images, next-gen formats, remove unused js

**URL:** <https://forum.ghost.org/t/ghost-properly-size-images-next-gen-formats-remove-unused-js/22233>\
**Category:** Developer help\
**Created:** [April 27, 2021, 10:05am UTC](https://forum.ghost.org/t/ghost-properly-size-images-next-gen-formats-remove-unused-js/22233 "2021-04-27T10:05:06Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![andrii](https://sea1.discourse-cdn.com/flex015/user_avatar/forum.ghost.org/andrii/32/11786_2.png) [@andrii](https://forum.ghost.org/u/andrii)\
**Post date:** [April 27, 2021, 10:05am UTC](https://forum.ghost.org/t/ghost-properly-size-images-next-gen-formats-remove-unused-js/22233/1 "2021-04-27T10:05:06Z")

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Hello team,

hosting Ghost 4 via Digital Ocean.

> **[Online Hikes](https://onlinehikes.com)**
>
> All things YouTube, coding and marketing

So, I tested it in lighthouse via [Measure page quality](https://web.dev/measure/)

The main performance issues are these:

- properly size images
- serve images in next-gen formats
- remove unused js

The main problem is with ghost publication cover in Casper theme [https://static.ghost.org/v3.0.0/images/publication-cover.png](https://static.ghost.org/v3.0.0/images/publication-cover.png)

You can check the issue here [https://lighthouse-dot-webdotdevsite.appspot.com//lh/html?url=https%3A%2F%2Fonlinehikes.com](https://lighthouse-dot-webdotdevsite.appspot.com//lh/html?url=https%3A%2F%2Fonlinehikes.com)

Any update how to serve publication cover in next-gen format and the best way to properly size it?

Thank you!

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<div class="post-metadata">

**Author:** ![script.gs](https://sea1.discourse-cdn.com/flex015/user_avatar/forum.ghost.org/script.gs/32/17430_2.png) [@script.gs](https://forum.ghost.org/u/script.gs)\
**Post date:** [April 21, 2022, 4:46am UTC](https://forum.ghost.org/t/ghost-properly-size-images-next-gen-formats-remove-unused-js/22233/2 "2022-04-21T04:46:50Z")

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Same Q 🙁

@andrii — were you able to find a fix for these?

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**Author:** ![TheRoyalFig](https://sea1.discourse-cdn.com/flex015/user_avatar/forum.ghost.org/theroyalfig/32/27771_2.png) [@TheRoyalFig](https://forum.ghost.org/u/TheRoyalFig)\
**Post date:** [April 21, 2022, 1:12pm UTC](https://forum.ghost.org/t/ghost-properly-size-images-next-gen-formats-remove-unused-js/22233/3 "2022-04-21T13:12:39Z")

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When images are hosted externally, they can’t be responsively optimized. For peak performance 🏎 , I’d download the image and upload a local copy. Then, I’d ensure that my theme is using the responsive image configuration as detailed here:

> **[How to use responsive images in Ghost themes](https://ghost.org/docs/themes/assets/#responsive-images-configuration)**
>
> Ghost themes support automatic image resizing, allowing you to use a minimal handlebars helper to output different image sizes.