I'll pre-empt by saying we can only do what the native front-end allows. So if the native front-end doesn't allow it, then we can't do it either using native widgets.
QuoteIs there a way to define an image in background window, layout grid ...
With regards backgroundImages, this was deprecated in version 2.50
http://4js.com/online_documentation/fjs-fgl-manual-html/#fgl-topics/c_fgl_Migrate_to_250_presentation_styles.html, prior to that the documentation had an entry in common style attributes for backgroundImage
http://4js.com/online_documentation/fjs-fgl-manual-html/#fgl-topics/r_fgl_presentation_styles_common_style_attributes.html after backgroundColor, and if you look up 2.40 documentation or earlier it will be there.
You may find that the deprecated behaviour is still there and functional, a quick test with
<Style name="*">
<StyleAttribute name="backgroundImage" value="http://4js.com/wp-content/uploads/2015/05/logo_4Js_2014_CMYK_seul-300x92.png" />
</Style>will show you where it applies (replace * with Window, Grid, Edit, or style selector etc to narrow down), but like any deprecated behaviour it is a case of use at your own risk. You may find that what works with Windows does not work with Mac, or a Windows update might stop it working etc.
For GBC, you can always use customisation with CSS and background-image property.
QuoteAnd in a button its possible to put an image in top and text in bottom ?
Does the native UI allow this? if it allows this consistently across the front-ends we support, expect to see a value here
http://4js.com/online_documentation/fjs-fgl-manual-html/#fgl-topics/r_fgl_presentation_styles_button_style_attributes.htmlIf you want non-native buttons, then what you can do is use Clickable Images, an IMAGE with an ACTION attribute (some examples
https://github.com/FourjsGenero/ex_clickable_image)
Hope that helps,
Reuben
