With image sequences, probably the biggest thing to address is the pixel x pixel sizes of the stills. For maximum performance (and quality in my book), I like to have those Scaled to match the Frame Size of the Project Sequence. The PNG format should be just fine, but size DOES matter. What are the pixel x pixel dimensions of your stills?
I do a lot of work with stills, but not usually in image sequences. For my work, I usually just leave the stills as PSD's, and never have any issues. These are Scaled to the Project, or only slightly larger (when I need to Pan on a Zoomed out image), and my Scaling is always done in Photoshop, prior to Import.
Thanks for your input.
I mean intermediate lossless image sequences, that use the exact pixel dimensions of my original 1080p footage. So there is no scaling involved. I'm just wondering if there are other factors that matter when choosing sequence presets? Like is Premiere somehow able to optimize the performance for AVCHD when I use and AVCHD preset or for DvcProHD when I use a preset for that? Or is the only thing that matters when choosing sequence presets simply the resolution and not the actual codec of the format?
Sorry. Had not picked that up, but on re-reading, I see that you mentioned that, and I just missed it.
Do not know why you are experiencing the slowdown there. Maybe others can offer something useful.
I work a lot with image sequences supplied from various sources.
I always convert them to a "movie" in AEFX and never use the seq. image files in PPRO.
I use an AEFX Comp that matches my PPRO Project (usually 720p).
I export it as an intermediate but you could DL the comp.