这里是我根据gif图像格式想出来的判断gif图像尺寸的方法,请大家给点意见 
    
    up.htm 
    
    <html> 
    <body> 
    <form action="up.asp" ENCTYPE="multipart/form-data" method="post"> 
    <table border=0 width=100% cellspacing="0"> 
    <tr> 
    <td width="30%">请选择您要上传的gif图片:</td> 
    <td width="70%"><input type="file" name="pic" style="font-size:10pt;"></td> 
    </tr> 
    </table> 
    <p align="center"><input type="submit" value="提交" style="font-size:9pt;background-color:#54B060;color:white;"> 
    </form> 
    </body> 
    </html> 
    
    
    up.asp 
    
    <% 
    
    FormSize = Request.TotalBytes 
    FormData = Request.BinaryRead( FormSize ) 
    
    bncrlf=chrb(13) & chrb(10) 
    divider=leftb(formdata,instrb(formdata,bncrlf)-1) 
    datastart=instrb(formdata,bncrlf & bncrlf)+4 
    dataend=instrb(datastart+1,formdata,divider)-datastart 
    Image=midb(formdata,datastart,dataend) 
    
    head_version = Ascb( midb( Image,1,3 ) ) 
    head_subversion = Ascb( midb( Image,4,3 ) ) 
    
    head_width_l = Ascb( midb( Image,7,1 ) ) 
    head_width_h = Ascb( midb( Image,8,1 ) ) 
    
    head_height_l = Ascb( midb( Image,9,1 ) ) 
    head_height_h = Ascb( midb( Image,10,1 ) ) 
    
    head_colors = Ascb( midb( Image, 11, 1 ) ) 
    
    head_width_h = head_width_h * 256 
    
    head_height_h = head_height_h * 256 
    
    
    head_colors = head_colors And &H07 
    
    Response.Write "图像大小为" & head_width_h + head_width_l & "x" & head_height_h + head_height_l _ 
    & "x" & 2^( head_colors + 1 ) 
    
    %> 
             
             
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