Use the Image bar to set the colour, contrast, and brightness options for the selected graphic object(s).
This icon on the Image bar opens the Image Filter bar, where you can use various filters on the selected picture.
Filter
Lists view attributes for the selected graphic object. The embedded or linked graphic object in the current file will not be changed, only the view of the object.
Graphics mode
With the Colour toolbar you can edit some properties of the selected object.
Specifies the transparency in the graphic object. Values from 0% (fully opaque) to +100% (fully transparent) are possible.
Transparency
Allows to crop the display of an inserted picture. Only the display gets cropped, the inserted picture is not changed. A picture must be selected to enable cropping.
In Impress and Draw no dialog is shown when you click the icon, but you see eight cropping handles. Open the context menu of a selected picture and choose Crop Image, if you want to use the dialogue box for cropping.
Drag any of the eight cropping handles to crop the picture.
Crop