Joomla! 3.6.5 + SEBLOD 3.10.0b
Field settings:
Upload - Image
1 Folder / Content - Yes/0755
Format / Object - JSON/Article/images[image_intro]
When I create a new article and upload image, in DB the path is stored without content-folder (it is created when the image is uploaded) and looks like {"image_intro":"images/05.jpg"}
When I edit this article and upload image a second time it is stored correctly with content-folder in the path {"image_intro":"images/33/05.jpg"}
How can I fix the problem in first upload?
You should not use JSON storage, it's usage is limited to special cases like with default Article intro image field.
Ok, then the question is how to upload Article intro image using standart upload-image field?
Why do you want to use Article intro? You can create new field with a correct storage and use that instead of article intro. In Seblod you can place any field in intro view. Otherwise I'm afraid you are stuck with default Article intro using media field.