I’ve been using GIMP to convert image files, mostly JPEGS but also sometimes TIFFs and/or 24-bit PNG, to 32-bit PNGs (adding an Alpha layer) on a fairly routine basis for a particular project, and am hoping I can utilize IrfanView instead to do many of the conversions in batch operations. When I do this via GIMP, I am selecting menu FILE > EXPORT…, giving the program a new PNG filename to export to, then selecting “8bpcRGBA” from the dropdown color scheme selector in the PNG options dialog, leaving all other options unchecked except for “Save thumbnail” and “Save color profile”. This gives an image file which is visually identical to the one I exported from, except that the new file is 32-bit whereas the old one was 24-bit, which is what I want as far as the image data goes. This exporting process, unfortunately, is time-consuming and cumbersome, and also results in the loss of some metadata, which I’ve tried experimenting with various metadata-related options to fix but no luck so far.
Anyway, I thought I’d try accomplishing what I want using IrfanView, but can’t seem to find a way to convert the files in a way that delivers new images which are 32-bit but look identical to the old ones. In IrfanView, I select menu FILE > BATCH CONVERSION/RENAME…, set output format to PNG, click on Options, and select the following options:
Save Transparent Color
Save Transparency as Alpha channel
I then start the batch, but am prompted for each image to select a color to be set as transparent. I don’t want to be prompted, and no matter what color I select, the newly converted image is NOT visually identical to the one it was converted from. Also, all metadata has again been lost.
If I also select “Use main window color for tranparency”, I’m no longer prompted to select a color, but the exported image STILL differs visually from the original, and metadata is still lost.
Is there a way for me to accomplish what I want with IrfanView? Ideally, I’d like to be able to do it via command line.
Anyway, I thought I’d try accomplishing what I want using IrfanView, but can’t seem to find a way to convert the files in a way that delivers new images which are 32-bit but look identical to the old ones. In IrfanView, I select menu FILE > BATCH CONVERSION/RENAME…, set output format to PNG, click on Options, and select the following options:
Save Transparent Color
Save Transparency as Alpha channel
I then start the batch, but am prompted for each image to select a color to be set as transparent. I don’t want to be prompted, and no matter what color I select, the newly converted image is NOT visually identical to the one it was converted from. Also, all metadata has again been lost.
If I also select “Use main window color for tranparency”, I’m no longer prompted to select a color, but the exported image STILL differs visually from the original, and metadata is still lost.
Is there a way for me to accomplish what I want with IrfanView? Ideally, I’d like to be able to do it via command line.
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