GIMP

GIMP

Change background to transparent
1. Layer > Transparency > Color to Alpha
2. From: (Click the Color box), then use eyedropper to select the colour u wish to make transparent.

Transform image (or Ctrl+G)
1. Tools > Toolbox
2. Select "Cage Transform"
3. Click on points around your image to surround it and complete the perimeter.
4. Drag and release the points to transform the image within

Text with outline
Method 1
1. Right-click on your layer containing text, then select "Alpha to Selection"
2. Select > Grow > 10px
3. Layer > New Layer > BucketFill black into the selected grown area
4. Drag the grown layer beneath the text layer
Method2
1. Write the text in the desired, font, size, colour
2. Set primary colour to the desired outline colour
3. Select by Colour tool (Shift+O), then click on the text
4. Edit > Stroke Selection > Line width: 1px > Stroke


Draw
1. Select "rectangle select tool" or "ellipse select tool"
2. Drag as required on your image
3. Edit > Fill with FG colour (Ctrl+,)


Copy an image1 and paste to another image2
1. Select all image1, then copy (Ctrl+C)
2. Go to image2, then paste (Ctrl+V)
3. You will see a new layer called "Floating Selection (Pasted Layer)" > Right-click on it then select "To New Layer"

Resize a particular layer
1. Select that layer
2. Toolbox > ScaleTool

Move an image around
1. Select that layer
2. Toolbox > Move Tool > ensure u click on the image to drag it (clicking on transparent area won't work)

Adjust layer size (rather than adjust the entire canvas)
Layer > Layer boundary size > Center

Fill all same colours with another colour where images are not contiguous
1. Select > By Colour > click on specific colour
2. Double-click on "Bucket Fill"
- select "FG color fill" (ensure you've set FG with your desired destination colour)
- select "Fill whole selection"
3. Click on an area which was selected earlier, and the entire image should change to your destination colour


How to distress an image in Gimp
Note: Ur PC will work faster with smaller images, so we shrink them, distress them, then expand them later.

Prepare distress layer
1. Open > textured image (google "crumpled paper", "rough texture", etc)
2. Image > Mode > Grayscale
3. Colors > Curves > make S-curve until all colours remain black and white only > OK
4. File > Export > save as png/jpg

Apply distress layer to design layer
1. Open > design layer
2. Shrink image size so that PC works faster:
Image > Scale Image > width to under 1000px > Scale
3. File > Open as layer > select distress layer which was prepared earlier
4. With distress layer selected:
- Scale Tool or Rotate Tool or Move Tool > adjust to fit design layer > OK
- Fuzzy Select Tool > click white area on distress layer > delete (this deletes white area, leaving distress markings)
- Select > Invert (this selects distress markings)
- click on Design Layer > Delete (this deletes areas overlapped by distress markings on the Design Layer)
- Hide (click the "eye") the Distress Layer;
- Select > None

Restore design layer to original size
- Image > Scale Image > width to original width > Scale

Save Image
- Export > save as png

Adjust opacity of fonts (useful for creating transparent watermarks)
- Ctrl+L

Vectorise a regular image
http://imgur.com/gallery/xL0Ba

How to do drop shadows (text, image, etc)
1. Select the layer containing the text/image/etc
2. Filter > Light and Shadow > Drop Shadow

How to warp an object within an image with GIMP
1. Select "Cage Transform" (Shift+G). Tool Options will show "Create or adjust the cage" chosen.
2. Click around the object to make a complete circle. Allow some space around the object.
3. Once a complete circle is made, the Tool Options will show "Deform the cage to deform the image" chosen.
4. Drag the nodes to warp the object as desired. Doubleclick on the circle to introduce extra nodes if needed. PRESS ENTER TO CONFIRM THE TRANSFORMATION.
5. You'll see remaining artifacts of the original image. To remove the artifacts: Select Free Select Tool (or click "F"). Draw a shape around the object, clicking in the spaces BETWEEN the artifact and the warped object.
6. Enlarge the image to cover the artifacts: Use the Scale Tool (Shift+T). Ensure u cover all artifacts. Then click the "Scale" button to confirm. What's remaining will be the small areas directly adjacent to AND surrounding the warped object (let's call it "Remnants").
7. Anchor the layer that contains the warped object (ensure the layer (called "Floating Selection (Transformation) is selected, then click the "Anchor" button.
8. To get rid of the Remnants: ensure the topmost layer (containing the warped object) is selected. Rightclick, then select "Add Alpha channel".
9. Select Eraser Tool (Shift+E). Select a soft brush (e.g. Brush "2. Hardness 050"). Then go to the image and start erasing the Remnants (on the top layer) to reveal the original background (on the bottom layer).
Source https://www.youtube.com/watch?v=jL8TepHX0qE

How to create round watercolour splash
1. File > New > Advanced Options> Fill with (Transparency)
2. Airbrush Tool (press "A").
3. Select one of these from Tool Options, e.g.: "Sponge 01", "Splats 01", "Texture Hose 03"
4. Click for few seconds and move cursor around to achieve desired effect.

How to create vignette
1. Image at bottom. Insert new layer on top (vignette layer).
Note: Be prepared to redo steps 2-4 as many times as necessary to achieve desired vignette area
2. Use "Ellipse Select Tool" (E), draw border of vignette (if redoing, draw a smaller circle)
3. Feather the donut: Select > Invert (Ctrl+I), then: Select > Feather > 100px (if redoing, raise the px)
4. Insert vignette colour: Bucket tool > select vignette colour > click on vignette area (donut)
5. If vignette effect was unsatisfactory, UNDO steps 4,3,2 and redo.

How to convert a photo/vector to pixel art 

https://www.youtube.com/watch?v=f5cVMqk-OB0 https://www.youtube.com/watch?v=XUkH6UoyfZQ

1. Open photo in GIMP 

2. Reduce colors of photo: Colors > Posterize > select a low number (e.g. 4) to group colors into fewer colors > OK

3. Crop area of interest: "Free select tool" > trace a complete area around object of interest > delete inverse of selected area

4. Shrink image: Image > Scale image > change to smaller width & height (e.g. 50px x 60px, 100px x 169px) > Scale > Zoom (Ctrl+plus) to see image become pixelated. IMPORTANT: the smaller the new width & height, the bigger the pixels

5. Crop to selection (delete unwanted outer areas surrounding object of interest)

6. Reduce colors further: "Select by Color Tool" > (adjust THRESHOLD slider if necessary in Tool options) > click on a pixel (a group of pixels with similar shades will be selected) > select desired color > select "Paintbrush tool" and paint over all selected areas

7. Enlarge image and maintain crisp edges of pixels: Image > Scale image > change to larger width & heigh (e.g. 500px x 600px) > Quality(interpolation: NONE) > Scale

8. Export as png