The method I have successfully used to display thumbnails that I have collected via screen capture or from online image sites is as follows
- Save the desired website in speed dial
- Obtain or create the new image that you would like displayed in Speedial and save ot as a 200x133(aprox) PNG file.
3.In C:\Documents and Settings\USER 1\Local Settings\Application Data\Opera\Opera\thumbnails locate the existing thumbnail and select rename. Highlight and copy the name
- Select the new PNG image, select Rename and paste the name from Opera's Speed dial image
- Delete the existing image from C:\Documents and Settings\USER 1\Local Settings\Application Data\Opera\Opera\thumbnails
- Paste the new renamed image in Opera's thumbnail file
- In Opera:config select User Preferences and goto Speeddial Thumbnail Request Header and de-select the checkbox