How to reduce size of .kmz file?

[SofiaAndersson1]

I'm trying to create a kmz-file from a image raster layer but in order to make the resolution of the file alright I have to choose something like 3000 pixels and 3000 dpi and I end up with a large file (8.3MB). I am using Layer To KML in ArcGIS Pro. I have an other map from an other data set which only takes up about 250KB but has a similar resolution, at least that's my visual interpretation. The maps areas are covering a same size area of 10x10 km. WHY are they so different in size and HOW can I reduce the size of the large file? I really need to make it smaller. ANY suggestions are welcome. I'm loosing my mind... Thank you!

[DanPatterson_Retired]

quite a large file to download, so I suggest you examine each raster layer's properties and confirm the extent, cell size, number of rows and columns ... and number of bands for each of the data sets.  Report those here.  

... halve the cell size quadruple the storage... for a single band

[LR]

Open your kmz (which is basically just a renamed zip file) and you'll see that one has a small JPG image while the other has a ~8mb PNG image. Change the image format. While PNG is good for images with large, uniform areas and will usually result in a smaller, lossless file, it's pretty bad for pictures with a lot of variation, such as photographs or already lossy/degraded images. Yours has hefty signs of JPG compression, which means there's lots of variation in it, leading to a large PNG.