images and form performance

[QB]

I am embedding 3 images on a form. i have resampled each of them to the size
they will be displayed in the form to try and reduce their size, but was now
wondering if there was a perfered format for embedding wihtin a form to get
the best performance/load time? Is bmp better than jpeg, or gif....?

I am currently using access 2003, but would also like to know the answer
relative to 2007 as well as we will be switching very shortly.

Thank you.

QB

 

[Allen Browne]

There's not a simple answer to this question.

An uncompressed BMP does not require the CPU to decompress it like a JPG
does, so if the CPU is really busy processing other tasks, it may load
faster. However, it takes up considerably more diskspace, and disk reads/bus
transfers are slower than CPU speeds these days, so it could be slower.

If you embed the image in A2003 or earlier, it bloats the MDB, so this disk
read may apply to loading the database, not merely the form.

Access 2007 is capable of embedding the compressed JPG format, which solves
the bloat problem. However, if you set the option to use this feature
(Office Button | Access Options | Current Database | Picture Property
Storage Format), then any previous version that opens the database won't be
able to show the picture.

If you are actually setting the Picture property of a form or report, you
may need to be aware that some versions of Access do not release this memory
properly, so if you open the form/report thousands of times without closing
Access, you may run out of memory.

If you are trying to store the picture, it might be better to use a text
field to store the fully qualified file name and load it into an image
property when needed. This avoids the whole bloating issue. It makes sense
to do this even in Access 2007 where you have the option of compressed image
storage, because the image control has a Control Source property that loads
the image for you without needing any code.

If it's a real issue, run some timing issues with typically database and
picture sizes on typical hardware, allowing for the effect of caching, and
see what you get.

Hope that helps you to make an informed choice.