Working with PictureBox

Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
    picDisplay.SizeMode = PictureBoxSizeMode.Zoom
    picDisplay.BackColor = Color.Black

    ' Load from a fixed path — file must exist
    picDisplay.Image = Image.FromFile("C:\Pictures\holiday.jpg")
End Sub

Public Class Form1

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Me.Text        = "Photo Viewer"
        picDisplay.SizeMode    = PictureBoxSizeMode.Zoom
        picDisplay.BackColor   = Color.Black
        picDisplay.BorderStyle = BorderStyle.FixedSingle
        OFGSelectImage.Filter  = "Image Files|*.jpg;*.jpeg;*.png;*.bmp;*.gif;*.webp|All Files|*.*"
        OFGSelectImage.Title   = "Select an Image"
        lblStatus.Text = "No image loaded."
    End Sub

    Private Sub btnView_Click(sender As Object, e As EventArgs) Handles btnView.Click
        If OFGSelectImage.ShowDialog() = DialogResult.OK Then

            ' Null-conditional Dispose — safe even if Image is Nothing
            picDisplay.Image?.Dispose()
            picDisplay.Image = Image.FromFile(OFGSelectImage.FileName)

            Dim img = picDisplay.Image
            Me.Text    = $"Photo Viewer — {IO.Path.GetFileName(OFGSelectImage.FileName)}"
            lblStatus.Text = $"✔  {OFGSelectImage.SafeFileName}  ({img.Width} × {img.Height} px)"
        End If
    End Sub

    Private Sub btnClear_Click(sender As Object, e As EventArgs) Handles btnClear.Click
        picDisplay.Image?.Dispose()
        picDisplay.Image = Nothing
        Me.Text        = "Photo Viewer"
        lblStatus.Text = "No image loaded."
    End Sub

End Class

' Zoom In — grow by 24×18 px each click
Private Sub btnZoomIn_Click(sender As Object, e As EventArgs) Handles btnZoomIn.Click
    picDisplay.Width  += 24
    picDisplay.Height += 18
    lblSize.Text = $"Size: {picDisplay.Width} × {picDisplay.Height}"
End Sub

' Zoom Out — minimum 80×60
Private Sub btnZoomOut_Click(sender As Object, e As EventArgs) Handles btnZoomOut.Click
    If picDisplay.Width > 80 Then
        picDisplay.Width  -= 24
        picDisplay.Height -= 18
        lblSize.Text = $"Size: {picDisplay.Width} × {picDisplay.Height}"
    End If
End Sub

' Toggle show/hide
Private Sub btnToggle_Click(sender As Object, e As EventArgs) Handles btnToggle.Click
    picDisplay.Visible = Not picDisplay.Visible
    btnToggle.Text = If(picDisplay.Visible, "Hide", "Show")
End Sub

' Rotate 90° clockwise
Private Sub btnRotate_Click(sender As Object, e As EventArgs) Handles btnRotate.Click
    If picDisplay.Image IsNot Nothing Then
        picDisplay.Image.RotateFlip(RotateFlipType.Rotate90FlipNone)
        picDisplay.Refresh()
    End If
End Sub

' Flip horizontally
Private Sub btnFlip_Click(sender As Object, e As EventArgs) Handles btnFlip.Click
    If picDisplay.Image IsNot Nothing Then
        picDisplay.Image.RotateFlip(RotateFlipType.RotateNoneFlipX)
        picDisplay.Refresh()
    End If
End Sub

Public Class SlideShow

    Private _images() As String = {
        "C:\Photos\slide1.jpg", "C:\Photos\slide2.jpg",
        "C:\Photos\slide3.jpg", "C:\Photos\slide4.jpg"
    }
    Private _current As Integer = 0

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        picSlide.SizeMode  = PictureBoxSizeMode.Zoom
        picSlide.BackColor = Color.Black
        Timer1.Interval    = 3000   ' 3 seconds
        LoadSlide(_current)
    End Sub

    Private Sub LoadSlide(index As Integer)
        picSlide.Image?.Dispose()
        picSlide.Image = Image.FromFile(_images(index))
        lblSlide.Text  = $"Slide {index + 1} of {_images.Length}"
    End Sub

    ' Tick fires every 3 s — advance and wrap around with Mod
    Private Sub Timer1_Tick(sender As Object, e As EventArgs) Handles Timer1.Tick
        _current = (_current + 1) Mod _images.Length
        LoadSlide(_current)
    End Sub

    Private Sub btnPlay_Click(sender As Object, e As EventArgs) Handles btnPlay.Click
        Timer1.Start() : btnPlay.Enabled = False : btnPause.Enabled = True
    End Sub

    Private Sub btnPause_Click(sender As Object, e As EventArgs) Handles btnPause.Click
        Timer1.Stop()  : btnPlay.Enabled = True  : btnPause.Enabled = False
    End Sub

    Private Sub btnPrev_Click(sender As Object, e As EventArgs) Handles btnPrev.Click
        _current = (_current - 1 + _images.Length) Mod _images.Length
        LoadSlide(_current)
    End Sub

    Private Sub btnNext_Click(sender As Object, e As EventArgs) Handles btnNext.Click
        _current = (_current + 1) Mod _images.Length
        LoadSlide(_current)
    End Sub

End Class

Imports System.Net.Http

Public Class Form1

    ' One shared instance — reused for all requests (best practice)
    Private Shared ReadOnly _http As New HttpClient()

    Private Async Sub btnLoadUrl_Click(sender As Object, e As EventArgs) Handles btnLoadUrl.Click
        Dim url = txtUrl.Text.Trim()
        If String.IsNullOrEmpty(url) Then Return

        lblStatus.Text     = "Loading…"
        btnLoadUrl.Enabled = False
        picDisplay.Image?.Dispose()
        picDisplay.Image   = Nothing

        Try
            ' Awaiting here — UI stays fully responsive during download
            Dim bytes = Await _http.GetByteArrayAsync(url)
            Dim ms    = New IO.MemoryStream(bytes)
            picDisplay.Image   = Image.FromStream(ms)
            lblStatus.Text = $"✔  {picDisplay.Image.Width} × {picDisplay.Image.Height} px"
        Catch ex As Exception
            lblStatus.Text = $"✘ Error: {ex.Message}"
        Finally
            btnLoadUrl.Enabled = True
        End Try
    End Sub

End Class