diff --git a/.appveyor.yml b/.appveyor.yml
index e3fc8e0..d2663fc 100644
--- a/.appveyor.yml
+++ b/.appveyor.yml
@@ -42,7 +42,7 @@ install:
   - SET "NEED_REBUILD="
 
   - IF NOT EXIST "Nim\\.git\\" (
-      git clone https://github.com/nim-lang/Nim.git
+      git clone --depth 1https://github.com/nim-lang/Nim.git
     ) ELSE (
       ( cd Nim ) &
       ( git pull ) &
@@ -80,7 +80,7 @@ install:
 
 build_script:
   - cd C:\projects\%APPVEYOR_PROJECT_SLUG%
-  - nimble install -y # > nul
+  - nimble install -y > nul
 test_script:
   - nimble tests
 
diff --git a/apidoc.md b/apidoc.md
index 88b1ce8..d9abe2d 100644
--- a/apidoc.md
+++ b/apidoc.md
@@ -37,7 +37,8 @@ decodePNG24(input: string, settings = PNGDecoder(nil)): PNGResult
 
 
 ```Nim
-# generic version accept T = `string`, `seq[uint8]`
+# generic version accept T = `string`, `seq[TT]`, or openArray[TT]
+# TT can be `byte`, `char`, or `uint8`
 encodePNG(input: T, w, h: int, settings = PNGEncoder(nil)): PNG[T]
 encodePNG(input: T, colorType: PNGColorType, bitDepth, w, h: int, settings = PNGEncoder(nil)): PNG[T]
 encodePNG32(input: T, w, h: int): PNG[T]
@@ -65,7 +66,7 @@ when not defined(js):
   saveAPNG(png: PNG[T], fileName: string): PNGStatus
 
 decodePNG(T: type, s: Stream, colorType: PNGColorType, bitDepth: int, settings = PNGDecoder(nil)): PNGResult[T]
-decodePNG(T: type, s: Stream, settings = PNGDecoder(nil)): PNG
+decodePNG(T: type, s: Stream, settings = PNGDecoder(nil)): PNG[T]
 
 type
   PNGRes*[T] = Result[PNGResult[T], string]
@@ -82,7 +83,18 @@ decodePNG24(input: T, settings = PNGDecoder(nil)): PNGRes[T]
 ## How to use PNGRes?
 
 ```Nim
-  let res = loadPNG32(seq[uint8], fileName, settings)
-  if res.isOk: result = res.get()  # get PNGResult[seq[uint8]]
-  else: debugEcho res.error()      # get error string
+  type
+    PNGPix = seq[uint8]
+
+  var pix: PNGResult[PNGPix]
+  let res = loadPNG32(PNGPix, fileName)
+  if res.isOk: pix = res.get()  # get PNGResult[PNGPix]
+  else: debugEcho res.error()   # get error string
+
+  # now you can access PNGResult as usual:
+  debugEcho "width: ", pix.width
+  debugEcho "height: ", pix.height
+
+  # draw(pix.data)
+  # or drawFrames(pix.frames) if it is a APNG
 ```
diff --git a/readme.md b/readme.md
index 1366ceb..dba2ce0 100644
--- a/readme.md
+++ b/readme.md
@@ -61,19 +61,19 @@ Supported color conversions:
 import nimPNG
 
 let png = loadPNG32("image.png")
-#is equivalent to:
-#let png = loadPNG("image.png", LCT_RGBA, 8)
-#will produce rgba pixels:
-#png.width -> width of the image
-#png.height -> height of the image
-#png.data -> pixels data in RGBA format
+# is equivalent to:
+# let png = loadPNG("image.png", LCT_RGBA, 8)
+# will produce rgba pixels:
+# png.width -> width of the image
+# png.height -> height of the image
+# png.data -> pixels data in RGBA format
 ```
 
 if you already have the whole file in memory:
 
 ```Nim
 let png = decodePNG32(raw_bytes)
-#will do the same as above
+# will do the same as above
 ```
 
 other variants:
@@ -89,9 +89,9 @@ to create PNG:
 special notes:
 
 * Use **loadPNG** or **savePNG** if you need specific input/output format by supplying supported **colorType** and **bitDepth** information.
-* Use **encodePNG** or **decodePNG** to do *in-memory* encoding/decoding by supplying desired **colorType** and **bitDepth** information
+* Use **encodePNG** or **decodePNG** to do *in-memory* encoding/decoding by supplying desired **colorType** and **bitDepth** information.
 
-pixels are stored as raw bytes using Nim's string as container:
+pixels are stored as raw bytes using Nim's `string`/`seq[T]` as container:
 
 |           Byte Order           |      Format      |
 |:------------------------------:|:----------------:|
@@ -100,7 +100,6 @@ pixels are stored as raw bytes using Nim's string as container:
 | grey1,grey2,grey3, ..., greyn  | GREY 8 bit       |
 | grey1,a1,grey2,a2,...,greyn,an | GREY ALPHA 8 bit |
 
-
 ## Animated PNG (APNG)
 
 Since version 0.2.0, nimPNG provides support for [Animated PNG](https://en.wikipedia.org/wiki/APNG).
@@ -126,7 +125,7 @@ Right now nimPNG is just a PNG encoder/decoder.
 
 The usual loadPNG and decodePNG can decode both unanimated and animated PNG.
 `png.width`, `png.height`, `png.data` works as usual. If the decoded PNG is an APNG, `png.data` will contains default frame.
-Animation frames can be accessible via `png.frames`. If it is not an APNG, `png.frames` will be nil.
+Animation frames can be accessible via `png.frames`. If it is not an APNG, `png.frames` will be have zero length.
 
 ### Encoding
 
@@ -156,7 +155,7 @@ the default image will be part of the animation. If `ctl` is nil, default image
   var str = png.encodeAPNG()
 ```
 
-* Final step is to call `saveAPNG` if you want save it to file or call `encodeAPNG` if you want to get the result in a string container
+* Final step is to call `saveAPNG` if you want save it to a file or call `encodeAPNG` if you want to get the result in memory.
 
 You can read the details of frame control from [spec](https://wiki.mozilla.org/APNG_Specification).
 You can also see an example in tester/test.nim -> generateAPNG