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Thumbnail extract from jpeg image

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Does anyone how to extract a thumbnail image from jpeg without loading it with ISHELL_LoadImage?

No, you must load the image before you can process it.

No, you must load the image before you can process it.

I can load it as stream of bytes but I can't use the ISHELL_LoadImage because of the memory limitation. I want to extract the thumbnail image because this is the only way that I can diplay the image.
ISHELL_LoadImage decompress the jpg image. For exapmple I have a 40 Kb jpg image. When it is loaded into the emulator it takes 900kb. So, you see why I should try another way to aproach this problem.

I can load it as stream of bytes but I can't use the ISHELL_LoadImage because of the memory limitation. I want to extract the thumbnail image because this is the only way that I can diplay the image.
ISHELL_LoadImage decompress the jpg image. For exapmple I have a 40 Kb jpg image. When it is loaded into the emulator it takes 900kb. So, you see why I should try another way to aproach this problem.

As far as I remember (I could be wrong), jpeg format spec does not specify thumbnail as a mandatory, so you might have no thumb stored at all. I'd reccomend you to check jpeg format spec so you'd be able to check if there is a thumb data stored and if so - read it as a raw data and process it somehow.

As far as I remember (I could be wrong), jpeg format spec does not specify thumbnail as a mandatory, so you might have no thumb stored at all. I'd reccomend you to check jpeg format spec so you'd be able to check if there is a thumb data stored and if so - read it as a raw data and process it somehow.

I tried open and read the file manually and judge whether it contains thumbnail,
nightmare work. But I've no memory to load all.

I tried open and read the file manually and judge whether it contains thumbnail,
nightmare work. But I've no memory to load all.