Our entry for the letter I deals with pictures rather than words:
Images – Many documents for translation include images of one kind or another, which are often not available or not provided at the translation stage. This can cause major problems.
Consider the assembly instructions for a piece of equipment, for example. Having the associated images will make it far easier to understand and render the instructions properly (after all, if the purchaser is not expected to assemble the equipment without images, despite having the thing in front of them, how can a translator be expected to understand the instructions without any visual assistance?).
Another issue is translation of picture captions. Something apparently straightforward in English, such as “A teacher supervises children in a snowy playground”, is impossible to translate accurately into a language like French without knowing the gender of the teacher, since the word for “teacher” will need to be either masculine or feminine accordingly. Translating without the associated picture means a 50:50 chance of choosing the wrong form in this case – and readers of the translation will instantly spot the mismatch if the gender is wrong.
Adverts are another area where having the image matters, since any linkage – subtle or otherwise – between the text and the image may otherwise be lost or distorted.
The bottom line is that translators need to see a document in all its glory to ensure that the translation is accurate and appropriate.