Use of Images
Human Abilities | Towards Understandable
Images | Uses of Images | Tips
for Optimal Use of Images
Human Abilities
For processing images humans can
- perceive them as a whole, that is, in parallel - while text is processed
sequentially,
- automatically group elements (Gestalt laws),
- put the focus on different groupings, that is, switch between foreground
and background information.
Towards Understandable Images
Motto: A picture tells more than a thousand words - but sometimes a
word tells more than a thousand pictures...
Prerequisites of the Reader
Appropriate prior knowledge is a prerequisite for understanding images, as
can easily be proven with technical drawings, medieval symbols, or scenes from
foreign cultures. Information is also implicit in images - they have to be "interpreted".
Thus, it depends on the reader how much information he or she can extract from
an image.
In addition, image readers need competence for
- recognizing relevant parts in an image
- organizing the information in the image
- interpreting the meaning of an image systematically
Also note that many people have difficulties in reading diagrams or images,
because there is no "primary" reading direction as in texts.
Last not least, readers need motivation to look at an image.
Image Quality and Embedding
Image interpretation is supported by good image quality and the proper embedding
into the context. Good image quality means
- sufficient technical quality,
- appropriate complexity of the presentation (not too high, not too low),
and
- correctness
Appropriate embedding into the surrounding text means, a.o.
- proper figure captions
- proper alignment of image elements with respect to the text (see tips)
- proper cropping of the image in order to avoid irrelevant image parts (see
tips)
Uses of Images
Decoration
- Images increase the attractiveness of texts or screens.
- Images may direct the attention to the text.
- Images support fun and motivation.
Presentation
- Images may repeat information in the text.
- Images may make the text information more vivid.
- Images may convey information that is absent from an equivalent text.
Organization
- Images can clarify or convey the structure of a text.
- Images may help to organize large quantities of knowledge or data.
- Images help to focus on relevant or critical aspects of data.
Interpretation
- Images clarify facts through image-based analogies.
- Images support (often fast) interpretations that are not easily possible
with text (e.g. determining angles or distances).
Memory
- Images help to better memorize (text) information.
Tips for Optimal Use of Images
Layout
- Divide the screen into a grid and decide where to place text and where
images.
Attention
- The upper left corner of a screen or page gets most attention.
Alignment
- Align images so that they point towards the text (if necessary and possible,
use a mirror image), not away from it.
Cropping
- If appropriate, cut the image (like in many famous paintings) or let the
image loom into the text; this saves space, but can also make the screen
look more attractive.
- Cropping (II): Crop images to the relevant section; make them as small
as possible and avoid irrelevant and distracting elements.
top