How crop photo with a circle

[Nisko]

I have a photo and would like to crop it into a circle and delete what's outside the circle.  How do I do this?  Thank you........

[Blighty]

1. Make sure the photo has an alpha channel.
Right click on the photo layer in the layers dialogue and click on Add Alpha Channel

2, Select the Ellipse Select Tool
In the Tool Options check Fixed Aspect Ratio and (1:1) for a circle.
If required, check Expand From Centre

3. Create your selection on the required portion of the photo

4. Select > Invert

5. Edit > Clear (or press the Delete key)
The outside portion becomes transparent, in Gimp represented by a chequer board pattern

6. SAVE as a .xcf file. EXPORT as a .png (jpg does not support transparency)

[Nisko]

Thank you for the very clear instructions. I think I understand most of what you explained - except for the transparency. I want to place the finished product on a white background (but it could be any color). What do I lose or give up by not being able to make it a jpg file? In other words, how is a png file different from a jpg file? Is it possible that the app I want to place the finished product in doesn't support a png file? Thank you.

PS: I haven't tried your instructions yet - but hope to sometime today or tomorrow (physical disability).

[rich2005]

(09-30-2017, 03:18 PM)Nisko Wrote: In other words, how is a png file different from a jpg file?  Is it possible that the app I want to place the finished product in doesn't support a png file? 

A jpg file does not support transparency. A png does. What sort of app will you use for your finished image?

I did this, with screenshots. Blighty gave the same procedure so not required but if you get stuck, have a look.

------
Lots of screenshots so not inline:

1. You might want to add transparency, an alpha channel to your image: https://i.imgur.com/6TOIgxr.jpg

2.  Use the elliptical selection tool. To create a circle, several ways but the most obvious is set the aspect ratio to 1:1
2a. The selection is resized on the canvas using the 'handles' that appear on sides and corners.
2b. Click and drag to move the selection around. https://i.imgur.com/sUYdmaI.jpg

3.  That selects inside the circle so now invert the selection. https://i.imgur.com/pFNgoYl.jpg

4.  Cut that bit of the image out: https://i.imgur.com/5JAW65c.jpg

5.  You might want a new background. Might be a new layer underneath or Export the image as a png to preserve transparency. https://i.imgur.com/4jhDbXe.jpg
5b. Or with your new background image already open, File -> Open as Layers the circular-cut-out png image.

[Nisko]

Thank you. I want to use the image next to my signature in Thunderbird email - all outgoing emails. Does that make a difference in what's in your last post? I suppose I could make the background, in this case, white.

[rich2005]

If you do not want a transparent background, just skip the first step, "Add transparency" or as Blighty wrote as a last step, exporting as a jpg loses transparency.

Quote:...I want to use the image next to my signature in Thunderbird email...

As a signature in Thunderbird, again I do not think it matters. The background colour will probably be white anyway.

Some points on Thunderbird.
AFAIK you cannot add an image to the HTML markup option - I could be wrong on that. For an image next to your 'signature' you might have to incorporate text with the circular image into one complete graphic.
In Gimp maybe something like this, several layers, save as an xcf for future modifications, export as a png or a jpg for use. https://i.imgur.com/UidKwuz.jpg

Then in Thunderbird, it will have to go in "attach signature from file" You could try HTML markup here, or I used my png file in the account settings: https://i.imgur.com/gzUTxHx.jpg
Looks like this when sending: https://i.imgur.com/KOHsLoD.jpg
and this on receipt in a browser, a mail client will be similar: https://i.imgur.com/ATcJUo5.jpg

best of luck.

[Nisko]

Again, you folks have been incredibly helpful - especially with the detail - and relative to me using Thunderbird. Thank you so much!