Hi everyone, I need some suggestions to fix my problem. When inserting (either using the dropdow menu or directly from an Explorer window) images, Layout tells me “not all of the specified content files could be inserted”. I tried using different file formats (.jpg, .bmp., .jpeg) but no results so far. Images are not huge (<1Mb). Hope you guys have any ideas of what’s going on. Thanks a million!
Are they using the CMYK colour space? AFAIK that works only on the Mac. Images should be RGB.
Thanks, Anssi, however Sketchup doesn’t mention this: Inserting Images | SketchUp Help
Also, I have no idea what colour space is used or how I can change the settings when saving an image
If you took the photos with your mobile phone, it may have the HEIC/HEIF extension. You can set the phone to convert them to JPG when you download them or convert them after, online or with Photoshop, Affinity. Check the extension of the photos.
I opened the Heic-files and saved them as (e.g.) .jpg-files. Without possibility to change settings though.
After sending them to my email I was able to use them. So probably it does have to do with the Heic-extension. Hopefully in next versions Layout is able to insert Heic-files as well.
Thanks everyone, topic may be closed.
Mark @mihai.s post as solution than we will know it is solved… 
In Samsung phones there is an option to set up at Gallery app > Settings > Convert HEIF images when sharing. Other phones probably have this feature as well.