load_image_from_stream_wx.py

# image_viewer.py

import io
import wx


class ImagePanel(wx.Panel):
    def __init__(self, parent, image_size):
        super().__init__(parent)
        self.max_size = 240

        img = wx.Image(*image_size)
        self.image_ctrl = wx.StaticBitmap(
            self, bitmap=wx.Bitmap(img))

        browse_btn = wx.Button(self, label="Browse")
        browse_btn.Bind(wx.EVT_BUTTON, self.on_browse)

        self.photo_txt = wx.TextCtrl(self, size=(200, -1))

        main_sizer = wx.BoxSizer(wx.VERTICAL)
        hsizer = wx.BoxSizer(wx.HORIZONTAL)

        main_sizer.Add(self.image_ctrl, 0, wx.ALL, 5)
        hsizer.Add(browse_btn, 0, wx.ALL, 5)
        hsizer.Add(self.photo_txt, 0, wx.ALL, 5)
        main_sizer.Add(hsizer, 0, wx.ALL, 5)

        self.SetSizer(main_sizer)
        main_sizer.Fit(parent)
        self.Layout()

    def on_browse(self, event):
        """
        Browse for an image file
        @param event: The event object
        """
        wildcard = "JPEG files (*.jpg)|*.jpg"
        with wx.FileDialog(
            None, "Choose a file", wildcard=wildcard,
            style=wx.FD_OPEN
        ) as dialog:
            if dialog.ShowModal() == wx.ID_OK:
                self.photo_txt.SetValue(dialog.GetPath())
                self.load_image()

    def load_image(self):
        """
        Load the image and display it to the user
        """
        filepath = self.photo_txt.GetValue()
        
        with open(filepath, "rb") as f:
            data = f.read()
            
        buff = io.BytesIO(data)
        img = wx.Image(buff)

        # scale the image, preserving the aspect ratio
        W = img.GetWidth()
        H = img.GetHeight()
        if W > H:
            new_w = self.max_size
            new_h = self.max_size * H / W
        else:
            new_h = self.max_size
            new_w = self.max_size * W / H
        img = img.Scale(int(new_w), int(new_h))

        self.image_ctrl.SetBitmap(wx.Bitmap(img))
        self.Refresh()


class MainFrame(wx.Frame):
    def __init__(self):
        super().__init__(None, title="Image Viewer")
        panel = ImagePanel(self, image_size=(240, 240))
        self.Show()


if __name__ == "__main__":
    app = wx.App(redirect=False)
    frame = MainFrame()
    app.MainLoop()