update installation page (#115)

FileIO has changed to not install IO backends for users, hence we need to install Image IO backends manually. The new docs explain this to new beginners. It also introduces the brand new ImageIO backend.

Author: johnnychen94

docs/src/assets/installation/mandrill.tiff

@@ -1,57 +1,77 @@
-# Getting started: Installation and testing your install
+# Getting started
 
-Most users probably want to start with the Images package, which bundles
+Most users probably want to start with the `Images.jl` package, which bundles
 much (but not all) of the functionality in JuliaImages.
 
 ## Installation
 
-Install Images via the [package manager](https://docs.julialang.org/en/v1/stdlib/Pkg/),
+Images (and possibly some additional packages) may be all you need to manipulate images programmatically.
+You can install `Images.jl` via the [package manager](https://docs.julialang.org/en/v1/stdlib/Pkg/),
 
 ```julia
 (v1.0) pkg> add Images
 ```
 
-This will also install many dependencies.
-
-Images (and possibly some additional packages) may be all you need to manipulate images programmatically.
-However, most users will want to take one or two additional steps:
-ensuring that you can load and display images.
-
 !!! note
     People in some regions such as China might fail to install/precompile `Images` due to poor network
     status. Using proxy/VPN that has stable connection to Amazon S3 and Github can solve this issue.
 
 ## Loading your first image
 
-When testing ideas or just following along with the documentation, it can be
-useful to have some images to work with.
-The [TestImages](https://github.com/JuliaImages/TestImages.jl) package bundles several "standard" images for you.
-If you haven't already installed it, use `pkg> add TestImages`.
-
-To load one of the images from this package, say
+If this is your first time working with images in julia, it's likely that you'll need to install some
+image IO backends to load the images. The current available backends for image files are:
+
+* [ImageMagick.jl](https://github.com/JuliaIO/ImageMagick.jl) covers most image formats and has extra
+  functionality. This can be your first choice if you don't have a preference.
+* [QuartzImageIO.jl](https://github.com/JuliaIO/QuartzImageIO.jl) exposes macOS's native image IO
+  functionality to Julia. In some cases it's faster than ImageMagick, but it might not cover all your
+  needs.
+* [ImageIO.jl](https://github.com/JuliaIO/ImageIO.jl) is a new image IO backend (requires julia >=v"1.3")
+  that provides an optimized performance for PNG files. Check benchmark
+  [here](https://github.com/JuliaIO/PNGFiles.jl/issues/1)
+* [OMETIFF.jl](https://github.com/tlnagy/OMETIFF.jl) supports
+  [OME-TIFF](https://docs.openmicroscopy.org/ome-model/6.0.0/index.html#ome-tiff) files. If you don't
+  know what it is, then it is likely that you don't need this package.
+
+These backends aren't exclusive to each other, so if you're a macOS user, you can install all these
+backends. And in most cases, you don't need to directly interact with these backends, instead, we
+use the `save` and `load` provided by the [`FileIO.jl`](https://github.com/JuliaIO/FileIO.jl)
+frontend. If you've installed multiple backends then `FileIO` will choose the most appropriate
+backend acoording to your file format. For example, if available `ImageIO` is used to load PNG
+files.
+
+Adding these gives you a basic image IO setup:
 
 ```julia
-using TestImages
-img = testimage("mandrill")
+(v1.0) pkg> add FileIO ImageMagick ImageIO
 ```
 
-If this is your first time working with images in Julia, it's likely
-that these commands will prompt you to install one or more additional
-packages appropriate for your platform; you should generally accept
-the recommendation, unless you have reasons to prefer an alternate
-solution.
+and to load an image, you can use
+
+```@example
+using FileIO
+using ImageShow # hide
+# specify the path to your local image file
+img_path = "/path/to/image.png"
+img_path = joinpath("assets", "installation", "mandrill.tiff") # hide
+img = load(img_path)
+```
 
-For loading image files that might already be on your computer, you should
-use the [FileIO
-package](https://github.com/JuliaIO/FileIO.jl):
+When testing ideas or just following along with the documentation, it can be useful to have some
+images to work with. The [TestImages.jl](https://github.com/JuliaImages/TestImages.jl) package
+bundles several "standard" images for you.
 
 ```julia
-using FileIO
-img = load("myphoto.png")
+(v1.0) pkg> add TestImages
 ```
 
-This should load the image for you, possibly prompting you to install
-an input/output package appropriate for your platform.
+To load one of the images from this package, say
+
+```julia
+using TestImages
+# backends such as ImageMagick are required
+img = testimage("mandrill")
+```
 
 ## Displaying images
 
@@ -62,17 +82,13 @@ display automatically:
 
 ![IJulia](assets/ijulia.png)
 
-Users of the Julia command-line interface (REPL) can install the [ImageView](https://github.com/timholy/ImageView.jl) package:
-
-```julia
-using TestImages, Images, ImageView
-img = testimage("mandrill")
-imshow(img)
-```
+Currently there're five julia packages can be used to display an image:
 
-`ImageView` includes interactive features (panning/zooming, contrast
-adjustment, playing movies, labeling, etc.) and may be of interest
-even for users of graphical environments.
+* [`ImageShow`](https://github.com/JuliaImages/ImageShow.jl) is used to support image display in Juno and IJulia. This happens automatically if you are `using Images`.
+* [`ImageInTerminal`](https://github.com/JuliaImages/ImageInTerminal.jl) is used to support image display in terminal.
+* [`ImageView`](https://github.com/JuliaImages/ImageView.jl) is an image display GUI. (For OSX and Windows platforms, Julia at least `v1.3` is required)
+* [`Plots`](https://github.com/JuliaPlots/Plots.jl) maintained by JuliaPlots is a general plotting package that support image display.
+* [`Makie`](https://github.com/JuliaPlots/Makie.jl) is also maintained by JuliaPlots but provides rich interactive functionality. 
 
 ## Troubleshooting
 

docs/src/install.md

@@ -301,16 +301,6 @@ it straightforward to keep track of the correspondence between
 location across multiple images. More information can be found in
 [Keeping track of location with unconventional indices](@ref).
 
-## Display
-
-Currently there're five julia packages can be used to display an image:
-
-* [`ImageShow`](https://github.com/JuliaImages/ImageShow.jl) is used to support image display in Juno and IJulia. This is automatically used when you use `Images`.
-* [`ImageInTerminal`](https://github.com/JuliaImages/ImageInTerminal.jl) is used to support image display in terminal.
-* [`ImageView`](https://github.com/JuliaImages/ImageView.jl) is an image display GUI. (For OSX and Windows platforms, Julia at least `v1.3` is required)
-* [`Plots`](https://github.com/JuliaPlots/Plots.jl) maintained by JuliaPlots is a general plotting package that support image display.
-* [`Makie`](https://github.com/JuliaPlots/Makie.jl) is also maintained by JuliaPlots but provides rich interactive functionality. 
-
 ## Examples of usage
 
 If you feel ready to get started, see the [Demonstrations](@ref) page for inspiration.