Item images are produced by taking screenshots. On this wiki the images should conform to the standard below.
As with all images, ensure your video options are at their highest to ensure the greatest image quality.
Furthermore, insure you are not at a player shop, as this causes the selling price to appear on the item information box.
Hover your cursor over the image so the item information box appears. Insure you are not at a shop, as the price will appear on the item.
Press the "Print Screen" key on your keyboard.
Paste the image into an image editing software program. (Note: I use Paint.NET as this gives me more control over the pixel selection)
Select a vague area around where the item box appears in the screenshot. Leave a fair bit of room. This is to make selection dragging easier.
Zoom into a corner of the item information box. You will see a 1 pixel thick border around the box. This is outer most pixel of the desired selection.
Carefully select from a corner of the item info box with the black pixels being the outermost perimiter of the selection.
Drag the selection so that it includes the whole of the item information box.
If it appears that only the item information box, with the whole of the 1 pixel thick black perimiter intact, is selected, click "crop".
Save the image as the name of the item. (Eg, if the item is "Lv 3 Air Powder" then name is "Lv 3 Air Powder". It's true name cannot always be saved, so if it's an item such as "Riding: Puppet Horse" then name it "Riding Puppet Horse")