Roll up your sleeves then, you have a lot of work to do...
For each and every folder that all of your individual blocks reside it, add them to the AutoCAD search path in OPTIONS command's FILES tab, top selection. Apply, SAVE, restart AutoCAD for it to take effect.
For each block, in CUI command's Commands-list section, start a new command then fill in all the required information you need.The macro is not rocket science, you just put in the following:
^C^C_INSERT;BLOCKNAME
If you don't want to be bothered with answering the remaining insert-command questions at the command line, add more semi-colons for each defaul answer it requires to insert. Note that each block with attributes prompts that require input will need to be accommodated with a pause in your macro code, which is done with a \ symbol.
Avoid the rookie mistake with macro writing: use a semi-colon for <enter> and never a blank space, they are easier to count.
DO NOT have an blank spaces in your block name, another rookie mistake with macro writing.
For the image for each and every block, you can either use the etch-a-sketch tool at the top right of the CUI section while you are in the command, or you can use Windows Snipping Tool to capture a screenshot of each and every block in a drawing file ans save it to PNG. Use a 3rd party Image Editing tool to resize the PNG image file to exactly 32x32 pixel size. Use the block name for the image name. Drop all images into a folder that needs to be added to the AutoCAD Search Paths (restart AutoCAD after adding it) before you go grab it in CUI command to add for each and every block.
That's it. Its all about trial and error on your end. Start now, you might be done in a week or ten.
Good luck.