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Maximum number of Pixels (Dimension)

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    Maximum number of Pixels (Dimension)

    I need to know what the maximum number of pixels that can be created for a jpg image. I found a post that related that the max dimension is 65500.

    65500 by 65500 is not going to work, is there a way to know the maximum number of pixels that will work?

    just to test the maximum dimension, I could create images:

    65500 X 3000
    3000 X 65500

    Simply put, is it an easy calculation, meaning maximum number of pixels, or is there some other limitation or approach?

    Thanks

    Jay
    Knows base times height equals area.
    Is that what the limitation is?
    The sky is blue, with a bit of white. Sometimes it is violet to purple. This is the correct answer.

    #2
    I think that it is determined mostly by the capacity of your computer. The more RAM, the bigger the image you can handle. If there is any limit imposed by the file type itself, most of us will not have to worry about it.
    Its: Belongs to "It"
    It's: Shortened form of "It is"
    ---------------------
    Lose: Fail to keep
    Loose: Not tight

    ---------------------
    Plurals do not require apostrophes

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      #3
      Limit = 2^29 pixels (probably)

      I did a little testing and the limit seems to be 2^29 pixels. I'm guessing that internally IrfanView requires 4 bytes per pixel, so 2^29 pixels requires 2^31 bytes (2 GB) which happens to be the most memory that can be allocated to a 32 bit application (which IrfanView is).

      FWIW, I was able to create a 35,000 x 14,636 (> 2^28.517 pixels) image but not 36,000 x 15,056 (2^29.014). I have 8 GB (2^33) of RAM, so I don't think the limit is hardware related.

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        #4
        It's partly hardware related...the other part is 32-bit system related. LOL. It isn't a problem for most people. Not so long ago I had 512MB of RAM and could hardly open some maps I needed to work with. That's gotten better, thank goodness. Now we have a better idea of what the ceiling is, anyway. Thanks.
        Its: Belongs to "It"
        It's: Shortened form of "It is"
        ---------------------
        Lose: Fail to keep
        Loose: Not tight

        ---------------------
        Plurals do not require apostrophes

        Comment


          #5
          The limit is not enforced by the physical memory size, but by numerous factors: how big is the virtual address space of the process (on 32 bit machines, 2^32 bytes/2=2^31 bytes, since the upper half is for the OS), how it is fragmented (if there's even a single virtual memory page used at, say, 2^16 bytes, it will limit the biggest chunk of memory available to 2^16 bytes), how much physical memory + swap space is available, how the conversion from the file saved to disk works (if it's a plain DIB no additional memory will be used for conversion, but in other cases some additional memory may be used to convert the file to the internally-used DIB), if the Undo feature is enabled (it requires an extra DIB of the same size of the image in memory), if the Paint plugin is used (it requires a temporary new copy of the DIB to work that is freed immediately, and another copy for the advanced eraser), how many bits per pixel the image use, if the resample option is enabled, ...
          IrfanPaint developer
          The latest stable IrfanPaint version is the 0.4.13.70.
          IrfanPaint is now open-source (released under BSD license).

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