Function FixImg(sString)
  
    Dim sReallyDo, regEx, iReallyDo
    Dim oMatches, cMatch
    Dim tStartTime, tEndTime
    If IsNull(sString) Then
        FixImg = ""
        Exit Function
    End If
    sReallyDo = sString
    On Error Resume Next
    sReallyDo = Replace(sReallyDo, vbCr, " ")
    sReallyDo = Replace(sReallyDo, vbLf, " ")
    sReallyDo = Replace(sReallyDo, vbTab, " ")
    sReallyDo = Replace(sReallyDo, "<img ", vbCrLf & "<img ", 1, -1, 1)
    sReallyDo = Replace(sReallyDo, "/>", " />", 1, -1, 1)
    sReallyDo = ReplaceAll(sReallyDo, "= ", "=", True)
    sReallyDo = ReplaceAll(sReallyDo, "> ", ">", True)
    sReallyDo = Replace(sReallyDo, "><", ">" & vbCrLf & "<")
    sReallyDo = Trim(sReallyDo)
    On Error GoTo 0
    Set regEx = New RegExp
    regEx.IgnoreCase = True
    regEx.Global = True
    '//去除onclick,onload等脚本
    regEx.Pattern = "\s[on].+""|\'])(.*"
    sReallyDo = regEx.Replace(sReallyDo, "")
    '//将SRC不带引号的图片地址加上引号
    regEx.Pattern = "<img.*""\'\s][^\""\'\s>]*).*"
    sReallyDo = regEx.Replace(sReallyDo, "<img src="/UploadFiles/2021-04-02/">

上面的代码确实写得不错，原理也可以参考下面的代码
js过滤img里style属性


var str = "<img style='ddddddddd'>"
str = str.replace(/<img[^>]*>/gi, function (match, capture) {
return match.replace(/style\s*"])[\s\S]*"htmlcode">

var is=document.images;
for(var i=0,len=is.length;i<len;i++){
is[i].style.cssText=""
}