The presence of pictures relevant to the text will assist learning. If you can replace the text with an image, do so. Pictures not covered by the information in the text will not enhance the learning of the text. If it does not have a purpose relevant to the text, remove it. The presence of pictures in the text will not aid the learning of the text which is not illustrated.
Pictures can help learners to understand what they read and also to remember it.
The memory's storing and recalling powers can be enhanced through the use of images for emphasis and association. Pictures can sometimes be used as substitutes for words or as producers of non-verbal information. Learners may fail to make full use of complex illustrations. Simple representations should not be discounted because they are not 'sophisticated' enough. If so, simplify it.