International Standards and Conformity Assessment for all electrical, electronic and related technologies
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Drafting IEC publications



Image file size

If the size of a Word file explodes while preparing a publication with many figures, reducing the size of the image files may also reduce the size of the Word document.


Normally, Word adjusts the size of inserted images automatically. However, working on the images before inserting them into the document gives you more control over file sizes, image size and quality.



If a Word document contains a lot of photographs, it can be useful to modify one or more of these parameters:

  • Dimensions - limit the height and width of your image to the dimensions required in the publication (they should not exceed 25 x 15 cm)
  • Quality / compression factor - your image may not need the highest output quality, so you may want to find a compromise between file size and quality
  • File format - ensure photographs are saved in .jpg as formats like .tif and .bmp usually have bigger file sizes

Please do not push the resolution below 200ppi (pixels per inch).


A few hundred KB should be sufficient for a multicolour, good quality image of A4 size at 200ppi; the file size of an image with reduced dimensions and/or medium quality should be much smaller.


Photo editing tools allow you to influence these aspects. Some editors even offer batch processing, allowing you to edit several photos at once.


All changes should be saved in copies of the original images. Please note that the quality of a .jpg file is reduced every time it is saved, so avoid unnecessary save-operations.


Embedding files in Word

If you embed big Excel, Visio or other files (via Insert > Object), they may increase the size of the Word document. In this case, export the image from the Excel chart or the Visio diagram to a non-editable file format and insert it in the Word document.