Hi @roger-vikstrom Can you provide any additional detail about the image that the transparent background is not working with? The image at the link you provided, of the camera, looks to have an opacity and background color applied to it. Did you want the background to be white like the background instead of black with opacity applied, making it appear grey?
Yes the opacity should be the same as the background.
Hi @roger-vikstrom, the Featured Image block has a setting for opacity that you’ll need to adjust in your Single template.
Go to Appearance > Editor
At the top of your page, click the template selector and then click “Browse all templates”
That should bring you to the Templates area of your site. You can also get there by visiting:
https://www.rvbild.se/wp-admin/site-editor.php?postType=wp_template
Click “Single” to access your single post template.
Select the Featured Image block placeholder
In the Settings panel on the right, drag the Opacity slider to 0, or type 0 in the Opacity box, as you see here:

Let us know how it goes!
You’re very welcome! I’ll mark this thread as resolved but feel free to start a new one if you have any other questions.