网上找的，未经验证。
<%
Class DealImgSize
dim aso
Private Sub Class_Initialize
set aso=CreateObject("Adodb.Stream")
aso.Mode=3
aso.Type=1
aso.Open
End Sub
Private Sub Class_Terminate
set aso=nothing
End Sub
Private Function Bin2Str(Bin)
Dim I, Str, clow
For I=1 to LenB(Bin)
clow=MidB(Bin,I,1)
if ASCB(clow)<128 then
Str = Str & Chr(ASCB(clow))
else
I=I+1
if I <= LenB(Bin) then Str = Str & Chr(ASCW(MidB(Bin,I,1)&clow))
end if
Next
Bin2Str = Str
End Function
Private Function BinVal(bin)
dim ret,i
ret = 0
for i = lenb(bin) to 1 step -1
ret = ret *256 + ascb(midb(bin,i,1))
next
BinVal=ret
End Function
Private Function BinVal2(bin)
dim ret,i
ret = 0
for i = 1 to lenb(bin)
ret = ret *256 + ascb(midb(bin,i,1))
next
BinVal2=ret
End Function
Function getImageSize(filespec)
dim ret(2),bFlag,p1
aso.LoadFromFile(filespec)
bFlag=aso.read(3)
select case hex(binVal(bFlag))
case "4E5089":
aso.read(15)
ret(0)="PNG"
ret(1)=BinVal2(aso.read(2))
aso.read(2)
ret(2)=BinVal2(aso.read(2))
case "464947":
aso.read(3)
ret(0)="GIF"
ret(1)=BinVal(aso.read(2))
ret(2)=BinVal(aso.read(2))
case "FFD8FF":
do
do: p1=binVal(aso.Read(1)): loop while p1=255 and not aso.EOS
if p1>191 and p1<196 then exit do else aso.read(binval2(aso.Read(2))-2)
do:p1=binVal(aso.Read(1)):loop while p1<255 and not aso.EOS
loop while true
aso.Read(3)
ret(0)="JPG"
ret(2)=binval2(aso.Read(2))
ret(1)=binval2(aso.Read(2))
case else:
if left(Bin2Str(bFlag),2)="BM" then
aso.Read(15)
ret(0)="BMP"
ret(1)=binval(aso.Read(4))
ret(2)=binval(aso.Read(4))
else
ret(0)=""
end if
end select
getImageSize=ret
End Function
Function Resize(ow,oh,rw,rh)
dim wh(1)
if cint(ow)>cint(oh) then
if cint(ow)>cint(rw) then
wh(0)=rw
wh(1)=int(oh/(ow/rw))
else
wh(0)=ow
wh(1)=oh
end if
else
if cint(oh)>cint(rh) then
wh(0)=int(ow/(oh/rh))
wh(1)=rh
else
wh(0)=ow
wh(1)=oh
end if
end if
Resize=wh
End Function
End Class
%>
'********************
' 使用方法
'********************
<%
Dim aa
Set aa=new DealImgSize
Dim pw,ph,rpw,rph
pw=aa.getImageSize(Server.MapPath("01.jpg"))(1)
ph=aa.getImageSize(Server.MapPath("01.jpg"))(2)
rpw=aa.Resize(pw,ph,160,120)(0)
rph=aa.Resize(pw,ph,160,120)(1)
Response.Write("<img src="http://www.webjx.com/01.jpg" width="&rpw&" height="&rph&">")
Set aa=Nothing
%>