I did the filmstrip tutorial, and for whatever reason I had it set to 300 ppi resolution but now want to have it set as 96 ppi so it will be easier to make smaller to fit into a blog page...or if not reset the resolution, at least have it resized to fit the 400 pixels of the column. Of course, the main attribute I want to keep is the sharpness of the pictures in the filmstrip as they are small and would be too hard to see if they were not super crisp. My need is....best way to make a picture smaller and keep it's sharpness or even gain sharpness, and should I re-do the resolution so the sizing works...or is there a formula I can use to make sure that with higher resolution that the size will end up the same as I use in lower resolutions pics.

ppi has relevance only for printing not on the quality of the images displayed on screen

And i believe they have no influence on the image file size, they are just a data for the printers, so reduce from 300 or even 1000 to 96 should not give any advantage if not maybe to limit unauthorized print

ok, if I have an image that is 1000 pixels, what will happen if I want my same image to be the same but 400 pixels wide, all proportions the same and what would be the best way for Gimp to resize it without ruining the sharpness?

Scale image , Bicubic or Laszlo interpolation (which the best depend from the image )
And you may always apply unsharpmask after scaling down if you want more sharpness

Hi PC,
That's not Laszlo but lanczos3 or sinc.
Gerard.

Thanks for the info...scale image lanczos3 or sinc.

And, as weirds as it seems, if you have a repetitive pattern in the picture that will get close to pixels size in the reduced image (fabric, roof tiles...) you must blur your image (gaussian blur, pixels= reduction ratio) before applying a reduction if you want to avoid moiré.

luckily, no repetitive pattern!