GetThumbnail Increasing Jpg File Size

[alecgregory]

I've been doing some work with the GetThumbnail function in FileMaker recently and I've found that GetThumbnail often creates files larger than the original, even though their pixel dimensions and dpi are lower.

 

For Example, My original file has the following spec:

• 300dpi
• 1000 x 1000 pixels
• 76,490 bytes

Using GetThumbnail ( Image; 750; 750 ) gives me an image that is

• 72dpi
• 750 x 750 pixels
• 85,579 bytes

So, a file that is a little over half the pixel area and less than a third of the dpi is over 10% larger than the original file.

 

That's not very good, is it?

 

Anyone care to suggest an explanation for this? Could it be because FileMaker is decompressing the image to process it and then re-compressing it really badly?

[ggt667]

Or they are adding unnecessary meta data.