How to load large images in memory ?

[ABU]

Loading a large image (2000x2000) may take several seconds (1..3) on
my old PC.
photo create image AAA -file aaa.jpg
and during this loading time, the user interface is not responding.

Using threads (package Thread) is not a solution, since different
threads have separate data space, and its "tsv" extension cannot work
with "image data" (I should convert the image-data in a binary string,
then I should pass this huge string from one thread to another, then
re-convert to 'image-data' ) ..... Noooo

Any link for an app (or better a library/package) able to manage large
images.

[Googie]

ABU wrote:

Thread package can be used anyway. Read file contents to a variable, share
the variable, encode value with base64 (somebody correct me if I'm wrong
about that one) and than use it in [image create photo AAA -data $var].

--
Pozdrawiam! (Regards!)
Googie