Hi @RichardGiles ,
I’m Richard at PageFly - Shopify Page Builder App, thank you for your question.
The ideal size for the featured blog image is 1800x1000 px. If you convert that to the aspect ratio, it would be 1.8:1
For pictures within your content, the recommended size is 1000x350 px.
Note: Just like other Shopify images, your blog images can’t be bigger than 4472x4472 px or more than 20 MB.
However, these measures aren’t set in stone. A lot will depend on how much screen you want your blog featured image to take up. It will also depend on the Shopify theme you use.
When it comes to images in your blog post, they should be around 600 px. And the image resolution should be 72 dpi.
Hope it helps.
Best regards,
Richard | PageFly Team