It likely depends on the field you are in and the amount of work and money you want to put into learning a new tool if you have only used Microsoft Word so far for this kind of task.
For example in the technical and scientific community you normally find a lot of fans of LaTex, which is free for anyone to use and offers incredible help with formulae. Have a quick look at the Introduction to LaTex to see if this is the kind of tool you need. If you need any help with it there is even a dedicated TeX.SE sister site that can help you with all sorts of problems for example if you need help with the Optimal arrangement of pictures/boxes in a page. There is also a lot of other information out there, for example Positioning images and tables.
Another tool that you will see recommended on this site quite often is Scrivener. I haven't used it so far, but apparently many writers often use it. It's a bit pricy though with $45 for the full version and there seems to be less information out there. For example by searching for scrivener pictures is:q I could only find this on Writing.SE: How to work with in-text markup for figures and captions in Scrivener?.
As you mentioned DTP, which according to Wikipedia often refers to software like Adobe InDesign (which is really expensive) I want to say that you can find help for such professional layouting tools on our sister site GraphicDesign.SE, who even have a tag about adobe-indesign who can help you with all sorts of very specific image problems in InDesign. I have never used this though, so take a look around the test version before thinking about buying and using this product.