Update sample image in README

+ a single letter option for `cimbar` cli encode mode?

README.md

@@ -8,7 +8,7 @@ Behold: an experimental barcode format for air-gapped data transfer.
 It can sustain speeds of 850 kilobits/s (~106 KB/s) using just a computer monitor and a smartphone camera!
 
 <p align="center">
-<img src="https://github.com/sz3/cimbar-samples/blob/v0.5/6bit/4cecc30f.png" width="70%" title="A non-animated cimbar code" >
+<img src="https://github.com/sz3/cimbar-samples/blob/v0.6/b/4cecc30f.png" width="70%" title="A non-animated mode-B cimbar code" >
 </p>
 
 ## Explain?
@@ -31,7 +31,7 @@ No internet/bluetooth/NFC/etc is used. All data is transmitted through the camer
 
 The code is written in C++, and developed/tested on amd64+linux, arm64+android (decoder only), and emscripten+WASM (encoder only). It probably works, or can be made to work, on other platforms.
 
-Crucially, because the encoder compiles to asmjs and wasm, it can run on anything with a modern web browser. There are [releases](https://github.com/sz3/libcimbar/releases/latest) if you wish to run the encoder locally instead of via cimbar.org.
+Crucially, because the encoder compiles to asmjs and wasm, it can run on anything with a modern web browser. For offline use, you can either install cimbar.org as a progressive web app, or [download the latest release](https://github.com/sz3/libcimbar/releases/latest) of `cimbar_js.html`, save it locally, and open it in your web browser.
 
 ## Library dependencies
 

src/exe/cimbar/cimbar.cpp

@@ -177,6 +177,7 @@ int main(int argc, char** argv)
 	unsigned compressionLevel = cimbar::Config::compression_level();
 	unsigned ecc = cimbar::Config::ecc_bytes();
 	options.add_options()
+		("n,encode", "Run the encoder!", cxxopts::value<bool>())
 		("i,in", "Encoded pngs/jpgs/etc (for decode), or file to encode", cxxopts::value<vector<string>>())
 		("o,out", "Output file prefix (encoding) or directory (decoding).", cxxopts::value<string>())
 		("c,color-bits", "Color bits. [0-3]", cxxopts::value<int>()->default_value(turbo::str::str(colorBits)))
@@ -185,7 +186,6 @@ int main(int argc, char** argv)
 		("z,compression", "Compression level. 0 == no compression.", cxxopts::value<int>()->default_value(turbo::str::str(compressionLevel)))
 		("color-correct", "Toggle decoding color correction. 2 == full (fountain mode only). 1 == simple. 0 == off.", cxxopts::value<int>()->default_value("2"))
 		("color-correction-file", "Debug -- save color correction matrix generated during fountain decode, or use it for non-fountain decodes", cxxopts::value<string>())
-		("encode", "Run the encoder!", cxxopts::value<bool>())
 		("no-deskew", "Skip the deskew step -- treat input image as already extracted.", cxxopts::value<bool>())
 		("no-fountain", "Disable fountain encode/decode. Will also disable compression.", cxxopts::value<bool>())
 		("undistort", "Attempt undistort step -- useful if image distortion is significant.", cxxopts::value<bool>())