I think your instincts are OK, but would tweak it somewhat.
1.1. Background: Basic issues in the field and history/related science. Few pages, WITH numbered subsections of 1.1.1, 1.1.2, etc. (Subsections are good--don't do a text splat!) A few basic clarifying images (from the field, not from your research) are totally fine here. In a teaching, explanatory mode, "here's the lay of the land", but not a deep analysis. If you feel the need/tendency to debate or discuss the historical work (or images) versus your results, I would do that in the results chapters, in the context of comparison to your research, not in Background. But simple clarifying images of the basic background are fine and even desirable.
1.2. Research objective: What you tried to do. And/or how the study evolved over time. E.g. narrowing/shifting scope, pursuit of a discovery. This should be a single short paragraph. No images or tables.
1.3. Thesis overview: This is also a single short paragraph, with no images or text. Do NOT call it "conclusion". And don't really summarize the findings. That belongs in the meat of the report, in the abstract or in the actual Conclusions CHAPTER. All you are doing here is giving a road map, describing the document. For example:
"Chapter 1, Introduction, reviews the history of dilithium research and the objectives of this project. Chapter 2, Experimental Methods, describes how the research was conducted. Chapters 3 through 5, respectively discuss the microstructure, macrostructure and Scottish dialect responsiveness of dilithium. Chapter 6, Conclusions, contains a brief summary of key findings as well as ideas for future research."
[rest of the thesis]
- Experimental methods [May not need to be a separate chapter. If you have methods that go from chapter to chapter, then I would do a methods chapter. For instance if you do a test that is used in 3 systems. But actually in this dilithium example, the methods are probably more different by section, so you might be better off doing them within the individual results chapters.]
2.3 or more (etc.)
3.3. more blas
Macrostructre (with numbered subsections)
Scottish dialect experiments (with numbered subsections)
Conclusions. [This chapter is optional, for a short document.]
6.1. Key findings (Will have a lot of overlap to Abstract. But no worries.]
6.2. Future research ideas (extension of the work, fixing things you couldn't fix during the project, etc.)
6.3. Implications [A carefully caveated discussion of how the research might affect dilithium vendors or spaceship captains/engineers. The idea is not to claim something you haven't proven, but also not the "hide the light under a bushel". Try to translate something to people in other fields. Of course with ample caveats if you have not done economic or operational assessments.]