不要在伺服器上儲存圖檔了

利用 The data: URI kitchen 吧。 產生的字串類似：

var src="<a href="data:image/png,%89PNG%0D%0A%1A%0A%0DIHDR
%10%08%06%1F%F3%FFa%02%A4IDAT8%8D%A5RMkSA%14%3Do%E6%E5%7D%A4I
%8CIj%954j%2B%ADE%B1-%B8%90%AA%20%A2%B8%90%20%8A%8B%82hWn%0AU
%04%C5b%DDt%A5%9B%FE%02%B1%08BtQp%A1%2B7B%09%8A%18%85%12%84BA
lMJcb%9A%F7%F2%F1%5E%DE%D7%8C%8B%B4%86%D0%EE%1C%18%98%7B9%9Cs
%E6%DE%23p%CE%F1%3FG%DC%B5%BB0%28%C1%2C%9D%E5%9C%F7%0B%02L%10
%FA%197%CB%3Fv%83%0A%1D%0E%DE_%26%CE%EA%C7%7B%96%D5%F3%98%85O
F%B8%BC%1F%E0.%88%B1%02Z%FD%B6%A8F%D8%5Dab3%BB%2B%01%7Bw%81%D
8%3F3%AF%EC%E0%A5qq%28%09%A2%86A%A3%87a%D6*%F0%D5%F2%60%D5%02
%BC%EF%CF%1A%FE%60%E9%8Ax%5B%FB%B0M%40%B6%1FN%EE%EB%03%5B%19%
1B%97%8E%9E%83%E4%AFC%8A%8A%F0%25FQ%A6a%C8A%1DRT%01%3D%3E%D1%
D5%D4%D4%05w%BE%BB%BB%83%C0%99%EFU%1D%2B0%A3%0C%9D%82%1C%D2%2
1%8A%1A%08%ABoA%18%08%D7%E0%93u%A8%FB%1C8%13q%1B%F6%FD%0E%02%
D6%AC%9D%27%D1%81%3D%BE%80%01%C1%D1%5B%03%DCF%0B%C1%19%60i%80
%A5%810%1Dj%7F%02%9E%A7%5C%ED%D8%02s1%E0%8B%86%218U%60%7B%A6%
96%DE%D2w%9B%40%23%0F8%3A%40%7C%A0r%0Fh%28r%04%F5%1C%10Hl%AD%
END%AEB%60%82</a>

直接利用

var icon=document.createElement('img');
icon.src=src;

即可（注意 IE 不支援）