Updated Cheat Sheet (markdown)

Cheat-Sheet.md

@@ -2,19 +2,79 @@ This cheat sheet describes the essential APIs that are commonly used. For the co
 
 # General
 
-## `Run`
+## `ebiten.Run`
 
 ```go
 func Run(f func(*Image) error, width, height int, scale float64, title string) error
 ```
 
-Run runs the game. `f` is a function which is called at every frame. The argument `(*Image)` is the render target that represents the screen. The screen size is based on the given values (`width` and `height`).
+`Run` runs the game. `f` is a function which is called at every frame. The argument `(*Image)` is the render target that represents the screen. The screen size is based on the given values (`width` and `height`).
 
 Ebiten tries to call f 60 times a second. In other words, TPS (ticks per second) is 60. This is not related to framerate (display's refresh rate).
 
 f is not called when the window is in background by default. This setting is configurable with `SetRunnableInBackground`.
 
-Run returns error when 1) OpenGL error happens, 2) audio error happens or 3) f returns error. In the case of 3), Run returns the same error.
+`Run` returns error when 1) OpenGL error happens, 2) audio error happens or 3) f returns error. In the case of 3), `Run` returns the same error.
 
 Don't call Run twice or more in one process.
 
+# Graphics
+
+## `ebiten.Image`
+
+```go
+type Image struct {
+    // contains filtered or unexported fields
+}
+```
+
+`Image` represents a rectangle set of pixels. The pixel format is alpha-premultiplied RGBA. `Image` implements [`image.Image`](https://golang.org/pkg/image/#Image).
+
+### `ebiten.NewImage`
+
+```go
+func NewImage(width, height int, filter Filter) (*Image, error)
+```
+
+`NewImage` returns an empty image. `NewImage` always returns nil error (so you can ignore that).
+
+`filter` argument is just for backward compatibility. If you are not sure, specify `FilterDefault`.
+
+### `ebiten.NewImageFromImage`
+
+```go
+func NewImageFromImage(source image.Image, filter Filter) (*Image, error)
+```
+
+`NewImageFromImage` creates a new image with the given image (source). `NewImageFromImage` always returns nil error.
+
+`filter` argument is just for backward compatibility. If you are not sure, specify FilterDefault.
+
+### `(*ebiten.Image).Clear`
+
+```go
+func (i *Image) Clear() error
+```
+
+`Clear` resets the pixels of the image into 0.
+
+`Clear` always returns nil.
+
+### `(*ebiten.Image).Fill`
+
+```go
+func (i *Image) Fill(clr color.Color) error
+```
+
+`Fill` fills the image with a solid color.
+
+`Fill` always returns nil.
+
+### `(*ebiten.Image).Size`
+
+```go
+func (i *Image) Size() (width, height int)
+```
+
+`Size` returns the size of the image.
+