Images attached to a record's images field can be viewed immediately in a data entry form, as long as the images field has been added to the form theme. The data entry grid has a Quickview and a Preview window to easily see the primary image or all images, respectively, for an images field.
Images in a Data Entry Form
To preview the images for an images field in the data entry grid, select the desired record and do one of the following:
Quickly View a Field's Primary Image — Move your mouse to hover over the 
Preview button for the images field you wish to preview. If a primary image is defined for the images field, that image will appear next to the record in a Quickview window. If no primary image is defined, the first image in the list of images for the images field will be displayed instead.
Images Field's Quickview
View All Images for a Field — Click in the images field you wish to preview. The Preview window appears, with all images added to the field and their descriptions showing in a grid. Once you're done reviewing the images, click 
Close to close the Preview window.
Images Field's Preview