How Can I Erase the Background of an Image?

[Freganzii]

It would be helpful to have a tool that helps to make a transparent background....and cut the main subject loose.

Example: I have taken a picture of a person and would like to store the person only, without environment.
Even with a white background it seems not possible now.

I'm convinced (but have not checked) that there will be different methods to tackle this.
A comparison with other software may guide you to the solution that you may like most.

[Bhikkhu Pesala]

If the image already has a (pure) white or uniform coloured background, just save the image as a transparent PNG or GIF, selecting the transparent colour as you save the image.

If the colour is not uniform, open IrfanPaint (F12) and use the flood-fill, paint brush, or colour replacer, tools to make the background a uniform colour.

IrfanView is not the ideal program for this task, but it already has the basic ability to do this.

[Frank]

We had this topic already in the forum!

see:
- "How to change the background of this photograph?"
- "rework an image - changin background of portait [a expert-one]"

see also:
- TokBlog → "Colorkey mit PhotoFiltre"
- GML Matting as a part of the GrowCut project (now it's Shareware), http://growcut.com/

[Mij]

There are two approaches to this as has been indicated in the posts above.

One is to "paint out" the background as Bhikkhu suggests. You can use the Irfanview Paint plugin for that either using the brush with a steady hand or with the assistance of the color replacer or flood fill tools if there is a clear color difference between foreground and background. The background area, now a single color, can then be selected as transparent when saving in PNG or GIF format.
I discussed this in the Irfanpaint thread starting in post 2 and resuming later around post 49. There was at that time available a free 8bf filter that could be used with Irfanview called GML matting both as a foreground cut-out tool and to replace the cut out onto a new background. As Frank says that filter is now part of GrowCut and is no longer free.
Irfanview does however now also have the ability to put back the transparent PNG or GIF onto a different background using the new Watermark/overlay tool in v4.32. Since this is not the primary purpose of the feature though there are some restrictions. On the whole, if you want to take this approach I think it would still be better to use a more dedicated program like the free Fotomix.

The other way is to use a "magic wand" tool to do the cut-out. Irfanview does not have this feature but they are found in a number of other image editing programs.