这个问题不是小问题。如果只是90度转，vb.net的picture控件有RotateFlip方法。
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任意角度，可以参考这个
;cs-lang=csharp
图片的变换涉及坐标处理，要自己算。
还有可以用Windows Presentation Foundation (WPF) 编程，里面的image控件好像也能旋转图片。
如果是VB6，恐怕只能用API函数了，百度一下“vb 旋转图片” “VB api函数”了解一下
vb.net 怎么来回切换图片?1、添加控件Picturebox1和控件Timer1，将Timer1的Interval属性改为1000（即1秒），Enabled属性改为True
2、假设你要循环切换4张图片，你可以添加如下代码即可实现：
Dim a As Integer = 0
Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
If a = 4 Then
a = 0
Else
a = a + 1
End If
If a = 0 Then Me.PictureBox1.Image = Image.FromFile("1.jpg")
If a = 1 Then Me.PictureBox1.Image = Image.FromFile("2.jpg")
If a = 2 Then Me.PictureBox1.Image = Image.FromFile("3.jpg")
If a = 3 Then Me.PictureBox1.Image = Image.FromFile("4.jpg")
End Sub
直接反转的没有，改用PictureBox 的绘图方法是可以的，只是稍为繁琐点。
如：
Picture1.PaintPicture LoadPicture("C:\Users\Administrator\Desktop\09.jpg"), Picture1.ScaleWidth, 0, -Picture1.ScaleWidth
就是只要把宽度或高度参数变为负值，就会返转换过来。左右反转的话，x轴的起点在图片框右边。纵向反转，Y轴上的起点在下边。
启动vb6建立一个标准exe工程，首先添加两个图片框（picture1和picture2），添加三个命令按钮command1（caption=“正常显示”）、command2（caption=“180度倒立”）、command3（caption=“45度旋转”），双击窗体，写入以下代码：
PrivateConstSRCCOPY=HCC0020
PrivateConstPi=3.14
PrivateDeclareFunctionSetPixelLib"gdi32"(ByValhdcAsLong, ByValxAsLong,ByValyAsLong,ByValcrColorAsLong)AsLong
PrivateDeclareFunctionGetPixelLib"gdi32"(ByValhdcAsLong, ByValxAsLong,ByValyAsLong)AsLong
PrivateDeclareFunctionStretchBltLib"gdi32"(ByValhdcAsLong, ByValxAsLong,ByValyAsLong,ByValnWidthAsLong,ByValnHeightAsLong, ByValhSrcDCAsLong,ByValxSrcAsLong,ByValySrcAsLong,ByValnSrcWidth AsLong,ByValnSrcHeightAsLong,ByValdwRopAsLong)AsLong
privateSubbmp_rotate(pic1AsPictureBox,pic2AsPictureBox,ByValtheta)‘45度旋转
Dimc1xAsInteger,c1yAsInteger
Dimc2xAsInteger,c2yAsInteger
DimaAsSingle
Dimp1xAsInteger,p1yAsInteger
Dimp2xAsInteger,p2yAsInteger
DimnAsInteger,rAsInteger
c1x=pic1.ScaleWidth\2
c1y=pic1.ScaleHeight\2
c2x=pic2.ScaleWidth\2
c2y=pic2.ScaleHeight\2
Ifc2x$#@60;c2yThenn=c2yElsen=c2x
n=n-1
pic1hDC=pic1.hdc
pic2hDC=pic2.hdc
Forp2x=0Ton
Forp2y=0Ton
Ifp2x=0Thena=Pi/2Elsea=Atn(p2y/p2x)
r=Sqr(1*p2x*p2x+1*p2y*p2y)
p1x=r*Cos(a+theta)
p1y=r*Sin(a+theta)
c0=GetPixel(pic1hDC,c1x+p1x,c1y+p1y)
c1=GetPixel(pic1hDC,c1x-p1x,c1y-p1y)
c2=GetPixel(pic1hDC,c1x+p1y,c1y-p1x)
c3=GetPixel(pic1hDC,c1x-p1y,c1y+p1x)
Ifc0$#@60;$#@62;-1ThenSetPixelpic2hDC,c2x+p2x,c2y+p2y,c0
Ifc1$#@60;$#@62;-1ThenSetPixelpic2hDC,c2x-p2x,c2y-p2y,c1
Ifc2$#@60;$#@62;-1ThenSetPi pic2hDC,c2x+p2y,c2y-p2x,c2
Ifc3$#@60;$#@62;-1ThenSetPixelpic2hDC,c2x-p2y,c2y+p2x,c3
Next
Next
EndSub
PrivateSubCommand1_Click()‘正常复制
Picture2.Cls
px=Picture1.ScaleWidth
py=Picture1.ScaleHeight
StretchBltPicture2.hdc,px,0,-px,py,Picture1.hdc,0,0,px,py,SRCCOPY
EndSub
PrivateSubCommand2_Click()‘180度倒立
Picture2.Cls
px=Picture1.ScaleWidth
py=Picture1.ScaleHeight
StretchBltPicture2.hdc,0,py,px,-py,Picture1.hdc,0,0,px,py,SRCCOPY
EndSub
PrivateSubCommand3_Click()‘45旋转
Picture2.Cls
Callbmp_rotate(Picture1,Picture2,3.14/4)
EndSub
PrivateSubForm_Load()
OnErrorResumeNext
Me.Caption=App.Title"添加应用程序标题
Me.Left=(Screen.Width-Me.Width)/2
Me.Top=(Screen.Height-Me.Height)/2"窗体具中
Picture1.ScaleMode=3
Picture2.ScaleMode=3
EndSub
