That’s probably because Dear ImGui is not for creating UIs for the average end-user. As explained in the Dear ImGui’s FAQs, it’s a renderer-agnostic GUI lib and does not provide any 2D/3D rendering utilities by default. People need to build their own 2D texture renderer for drawing images. Although this can be done in a couple of lines using quite a few knowledge in 3D graphics, the learning curve may look steep for those who don’t have any relevant background. Maybe I should add a default 2D image renderer to CImGui.jl. I’m still looking for a way to integrate ImGui with other 2D plotting tools in the Julia ecosystem, so stay tuned. 
My personal use case is to build simple GUI tools for 3D computer vision tasks like IntelRealSense-viewer or open3d. I feel like Dear ImGui is the perfect tool for this kinda use case. The learning curve of its API is really flat.