Ive followed the best practice to convert images from jpg/jpeg to PNG by manually converting image on my Mac machine and using java library (Java 8 ImageIO and iCafe) to convert an image. It turned out that two method gave me two different result even though it looked the same by looking at the properties
1. Export image as PNG
2. convert image by using iCafe. I set the parameters as the following
ImageIO.write(img, fo, imageType, builder.quantMethod(QuantMethod.WU_QUANT) .colorType(ImageColorType.INDEXED) .applyDither(true) .ditherMethod(DitherMethod.FLOYD_STEINBERG) .hasAlpha(true).build());
I'm running out of ideas now. I'm wondering if you technical team suggests me which library I can use to convert images.