如何在HTML文件中重复使用base64图像

I have an HTML file that will be portable to distribute to clients. It has an index of documents. I want a PDF or Word icon for each document but I don't want to repeat the base64 string 30 times if I can avoid it. How should I do this? Javascript is okay, but my goals are simplicity and portability.I have an HTML file that will be portable to di