VB.net aspX image resize and created file permission denied

Question

I'm trying to create an image based on an original image as a template.

a picture > kapak.jpg - resize to 1366x768 > orta.jpg - resize to 848x480

Code is working. Nothing wrong BUT when I use; code block 2 its locking the file which is kapak.jpg

I can't delete or rename etc. Even if I close the browser or vstudio or all. Nothing changes but restart the iis. I even cant delete it on the file browser as well. It's just locking it and doesnt allow anything. it says that; w3wp.exe or iis express worker is using this file so you cant delete or etc. Access denied.

I tried dispose or =nothing for bitmap moved code block 2 to another sub nothing changed.

If I dont use code block 2 it creates and allows me to delete or rename etc.

Any suggestions will be appreciated. How can I set free the file?

button_1_click

gelenIMG.ImageUrl = "\dene_2.jpg"

Dim uzatBOYfark As Integer
Dim uzatENfark As Integer
Dim kapakRESIMayar As New Rectangle(0, 0, 1366, 768)

uzatENfark = kapakRESIMayar.Width : uzatBOYfark = kapakRESIMayar.Height

Using orijinalRESIM = Image.FromFile(Server.MapPath(gelenIMG.ImageUrl))
If orijinalRESIM.Width < kapakRESIMayar.Width Then uzatENfark = kapakRESIMayar.Width * (kapakRESIMayar.Width / orijinalRESIM.Width)
If orijinalRESIM.Height < kapakRESIMayar.Height Then uzatBOYfark = kapakRESIMayar.Height * (kapakRESIMayar.Height / orijinalRESIM.Height)

Using kapakZEMINsablon = New Bitmap(kapakRESIMayar.Width, kapakRESIMayar.Height)
Using grp = Graphics.FromImage(kapakZEMINsablon)
grp.Clear(Color.Red)
grp.DrawImage(orijinalRESIM, New Rectangle(0, 0, uzatENfark, uzatBOYfark + 1), kapakRESIMayar, GraphicsUnit.Pixel)
End Using
kapakZEMINsablon.Save(Server.MapPath(geciciRESIMyeri & "\kapak.jpg"), Imaging.ImageFormat.Jpeg)
End Using
End Using
imgKAPAK.ImageUrl = geciciRESIMyeri & "\kapak.jpg"


code block 2:
Dim bitmapORTA As New Bitmap(Image.FromFile(Server.MapPath(imgKAPAK.ImageUrl), True), 848, 480)
bitmapORTA.Save(Server.MapPath(geciciRESIMyeri & "\orta.jpg"), Imaging.ImageFormat.Jpeg)
imgORTA.ImageUrl = geciciRESIMyeri & "\orta.jpg"