无解,没有属性可以控制文件背景。
https://learn.microsoft.com/en-us/previous-versions/ms536473(v=vs.85)#elementsobjects
<HTA:ApplicationID="oHTA"
Applicationname="myApp"
border="thin"
borderstyle="normal"
caption="yes"
icon="filename.ico"
maximizebutton="yes"
minimizebutton="yes"
showintaskbar="no"
singleinstance="no"
sysmenu="yes"
version="1.0"
windowstate="normal"
scroll="yes">
把icon="filename.ico"的背景图设置为透明