Send an answer to a topic: Question about JPEGs
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antp
If you would not have saved them to jpeg if you cropped them directly, yes there is a small quality loss.
For that reason bmp or png is a good choice as temporary format, as it is lossless: I batch-convert my bmps only when I upload the pictures.
For that reason bmp or png is a good choice as temporary format, as it is lossless: I batch-convert my bmps only when I upload the pictures.
G-MANN
I'm asking because I did some DVD captures last night, but I didn't have time to crop away the black borders before I saved them. If I open them, take away the borders and save them again, will the quality suffer more, than if I had done the cropping last night and saved them just once?
antp
I edited my message. Actually they do not really compress "more", there is just a loss of info each time, and that depends on the compression ratio chosen. It is hard to give any number.
G-MANN
How much do they compress each time?
antp
Depends what you mean by "the more you save them" and "more compressed".
Each time you open and resave a file, there is a loss of quality.
That loss of quality includes detail loss, and less details means that the file is easier to compress (i.e. smaller).
If you save multiple times a file without closing it, it is like if only last save counts.
That's why the JPEG conversion should only be done at the end, after resize/cut operations.
Each time you open and resave a file, there is a loss of quality.
That loss of quality includes detail loss, and less details means that the file is easier to compress (i.e. smaller).
If you save multiple times a file without closing it, it is like if only last save counts.
That's why the JPEG conversion should only be done at the end, after resize/cut operations.
G-MANN
Is it true with JPEG picture files the more times you save them, the more they are compressed?