Document integration images don't render when opening files from nvim-tree or revisiting buffers

[charlesg3]

Problem

The document integration in lua/image/utils/document.lua sets up autocmds to detect window/buffer changes and re-render images:

vim.api.nvim_create_autocmd({ "WinNew", "BufWinEnter", "TabEnter" }, {

BufEnter is missing from this list. BufWinEnter only fires the first time a buffer is displayed in a window — it does not fire when revisiting an already-loaded buffer. This means images fail to render in common workflows:

• Opening a file from nvim-tree: selecting a markdown file from the tree opens it in an adjacent window, but if the buffer was previously loaded, only BufEnter fires (not BufWinEnter), so images don't render
• Switching buffers: :bnext, :bprev, or buffer pickers switching to a previously-visited buffer only fire BufEnter

Steps to reproduce

1. Open a markdown file with images via a document integration (e.g. diagram.nvim)
2. Navigate away (e.g. open another file, or focus nvim-tree)
3. Return to the markdown buffer via nvim-tree, :bnext, or a buffer picker
4. Images don't render until another trigger fires (e.g. :e to reload)

Expected behavior

Images should re-render whenever a buffer with a document integration becomes active, regardless of whether it was previously loaded.

Suggested fix

Add "BufEnter" to the autocmd event list. BufEnter fires every time a buffer becomes active in a window, complementing BufWinEnter (first display only), WinNew, and TabEnter.