PreviewImage: Remove PNG support (to clean dependencies)

preview/PreviewImage.cpp

@@ -11,7 +11,6 @@
 #include "../common/DiffractionGeometry.h"
 #include "../frame_serialize/CBORStream2Deserializer.h"
 #include "../compression/JFJochDecompress.h"
-#include "JFJochPNG.h"
 
 constexpr const static rgb lime = {.r = 0xcd, .g = 0xdc, .b = 0x39};
 constexpr const static rgb pink = {.r = 0xe9, .g = 0x1e, .b = 0x63};
@@ -263,8 +262,6 @@ std::string PreviewImage::GenerateImage(const PreviewImageSettings& settings,
             return WriteJPEGToMem(rgb_image, settings.jpeg_quality);
         case PreviewImageFormat::TIFF:
             return WriteTIFFToString(rgb_image);
-        case PreviewImageFormat::PNG:
-            return WritePNGToMem(rgb_image);
         default:
             throw JFJochException(JFJochExceptionCategory::InputParameterInvalid,
                                   "Preview image format not supported");