5 Replies Latest reply on May 9, 2017 7:07 AM by TSGal

    GetThumbnail Control


      When attempting to downsize an image for conservation of disk space, I've noticed that the GetThumbNail function does not allow precise control over the resulting file size. My objective is to determine if an image is above a target Filesize (in this case 200k) and if so, reduce it to the target size (approximately, allowing some wiggle room for rounding, file compression, etc).


      Whenever a new pixel dimension is specified for GetThumbnail, the function performs some very questionable handling of the new image.


      In my Capture 1, an image is being "thumbnailed" to it's actual size, and retains the same file size (563k at 180 DPI).


      In Capture 2, the horizontal resolution requested has been reduced by 1 pixel. The resulting file size has plummeted to 162k, and the actual DPI has been factored down from 180 to 72.


      I come from a graphic arts background, and have a decent understanding of image file properties (pixels, inches and DPI). This result seems to fly in the face of most image editing software (Photoshop). The pixel dimensions are unrelated to the DPI, the DPI relating to the dimension in inches ( Pixels / DPI = Inches ) of the image.


      I'd like to report this as a bug, unless anyone can offer something I'm missing here. Any input is appreciated.


      FMPA 13.05 and 14.04

      Windows 2008 R2 Server

        • 1. Re: GetThumbnail Control



          Thank you for your post.


          I am able to verify a thumbnail image is rendered at 72 DPI under FileMaker Pro 14.0.4.  I have forwarded your post along with my findings to our Development and Testing departments for review.  When I receive any feedback, I will let you know.



          FileMaker, Inc.

          • 2. Re: GetThumbnail Control



            Development has informed me that thumbnails are always 72 DPI.  When you provide the same dimensions as the image, there is no processing needed, so it just passes back what you provided.


            Since this isn't documented anywhere, the manager of our Documentation has been notified so that it can be addressed in a future release.



            FileMaker, Inc.

            • 3. Re: GetThumbnail Control

              My reason for mentioning, is that the nature of the function suggests a

              precise level of control, that simply does not exist.

              A requested 1% reduction in total pixels should not result in a loss of 72%

              of the image data. The un-requested 2nd reduction

              to 72 DPI makes the resulting image largely uncontrollable with the current



              That precision of control and logical functioning is available in at least

              2 old plugins. I've attached a screenshot of the same

              test being performed with the CNS Image plugin [ CNSImage_Resize( Image ;

              Width ; Height ) ], which yields a logical reduction

              in the file size. Surely, this must have been the intent of the

              GetThumbnail function?


              However it may be documented in the future, in it's current form, it's

              going to remain very limited in it's usefulness, and very

              counter intuitive to those people who do work with images regularly. I do

              understand that Filemaker is not Adobe Photoshop,

              and that technical issues may make this something that is not of enough

              value strategically, to change the programming.


              My only intent today is to assure that I've communicated my concern

              adequately. I sincerely appreciate your response and

              any future followup.


              Mark D Kerr

              • 4. Re: GetThumbnail Control



                Your concern has been noted.



                FileMaker, Inc.

                • 5. Re: GetThumbnail Control



                  With the release of FileMaker Pro 16, the Help documentation has updated the GetThumbnail section:


                  FileMaker Pro 16 Help


                  "The thumbnail image always maintains the proportions of the original image and has a resolution of 72 dpi."



                  FileMaker, Inc.