And on this forum and don’t see my question answer already.
For GhostPro customers are the official themes set to convert images to webp and/or avif?
If not, how can I do that? So far I just see info on how to do this for self-hosted Ghost sites, editing the img helper, which I don’t think applies to GhostPro customers.
Expected user story: for GhostPro customers any image they upload is converted to webp or avif.
If not, if I upload webp will GhostPro serve that file, or will it reprocess the image to jpeg?
Don’t see any info about this so clarification is appreciated.
Any theme can be updated to specify image conversion, including official themes. (You’d download it, make your changes, zip it back up with a different name, and upload it again. This assumes you aren’t on the starter plan.)
Official themes are hit and miss. For example, Source converts to webp for post cards (the small cards on the homepage and other collection routes) but not for feature images shown on post and author pages. Casper doesn’t convert. (Note: Both of these themes generally use srcsets to load the right size image. They just don’t direct Ghost to load a different format.)
Worth noting that whether or not it makes sense to convert is rather situational. For example, if you have your images as highly size-optimized jpgs, then you wouldn’t actually want Ghost to convert them to webp, because webp will be larger than small jpeg. However, if you want to just drag and drop any old image on your computer without thinking about optimization, then yes, you want a theme that converts for you, absolutely.
It’d be awesome if img_url were a little bit ‘smarter’ about how it handles images. I’d love to have a helper that converted big pngs to webp, but left the small jpegs alone. That’d be pretty sweet.
I’m on the starter plan just to get me past the learning curve.
Just to clarify… if I make my own webp images they are hosted as is when I add them to a post/page? And if I use the image editor UI to crop etc it still keeps webp images in webp format?
Thanks to both of you, Cathy and Jon. I forgot there was email support since so many SaaS apps just have forum support. I emailed detailed questions and am waiting on answers.
Part of the reason I asked is because the docs say — “Uploaded images will be automatically optimized for the web with lossless compression” — which sounds like it’s reprocessing and not using images as is.
Can this be explained more clearly?
(edited to remove question about lossless over lossy formats)
Keep in mind that if you’re on the Starter plan on Pro, you’ll be using the defaults baked into your theme, but this is a good read on this topic, I think, and it explains what is happening in the background: Image Optimization in Ghost
Update from emails with GhostPro support, I’ll summarize for any future people searching for clarity about all this.
When uploading images, the supported image formats you use are preserved in Ghost, and used as is if they are 2000px in width or smaller. However if you upload an image format that is wider than 2000px it will be reprocessed to 2000px max width. e.g. A jpeg that is 3000px in width and created at 50% quality, will be reprocessed to be 2000px wide and saved at 80% quality.
So if you want the best optimized images you should optimize them on your end, making sure to keep all images to be 2000px or smaller in width.
Also, as of writing, support says the Source official theme by default is set to save all feature images as webp image format.
If there’s anything incorrect about this please let me know.
Much appreciated all!
That might be a bit of a miscommunication. Themes don’t save images. Source does direct the featured images in cards (like on the homepage) to be served as webp. It doesn’t cause the feature image to be served as webp on single post pages.
Thanks for verifying Cathy. About themes and image formats isn’t the manual code change to specify image format settings part of the theme’s code? If it’s not I missed where that image format code is set.
Sharing tests for any future people searching about this.
Okay I like to be exacting and detail oriented, especially when learning a new tool/platform, and just did some tests since the Images documentation here: Editor cards
says:
“Uploaded images will be automatically optimized for the web with lossless compression”
But support@ghost said:
When uploading images, the supported image formats you use are preserved in Ghost, and used as is if they are 2000px in width or smaller.
In testing I found that the ghost’s support documentation is correct about image reprocessing in all cases. In no tests are images used as is. (Not sure about lossless since the ghost reprocessed image size seems like they are all lossy, as expected. Lossless would be much larger… not sure why the docs say that.)
Here are my tests and results:
Image pipeline:
iphone heic source > macos photos app adjustments > save as modifed heic > resize and save as webp 80 quality in photoshop 2025 = my optimzed webp for ghost.
For best results optimize your images as if they would be used as is. Ghost’s forced reprocessing will be minimal and acceptable.
Do not upload large non-optimized images to ghost, its reprocessing will be unacceptable if you care about image quality and have time/workflow to do better.
