If Image should display for all the sheets of dashboard then App option is preferable. However if image is specific to some data and sheet than "Text and Image" can be use. 1) App Option : Image can be aligned as left\Center\Right . Going to apply for all sheets you would be creating. We are using the same for display Company logo.
App Option >> Image >> Image alignment
2) Text and Image : Option can be use but image is going to display in work area of dashboard.
The steps u have mentioned is what actually i have done.
after uploading the image in App Option, the image gets reflected in all the sheets of the app.(Agreed)
Irrespective of pixel size, whichever image we upload into App Option within screen returns to fixed size, i need to know if there is any option to show the image bigger (I dont want to use text and image option which eats up the sheet space)