Problem with masking

[keloniton]

Hello,
I am trying to use masking and make some images. But what ever i do there is a white surrounding my final image, I also use /5 and *5, but still the same problem. Please help me.
Here is my propmt:
FIRST PROMPT:
imagine --init-image T18.jpg --mask-prompt "shoes AND NOT (white surrounding){-5}" --mask-mode keep "commercial photography, a pair of shoes, black background, very detailed, high resolution, highly detailed, high quality" --negative-prompt "unreal, unrealistic, ugly, bad quality, not real, deformed iris, deformed pupils, semi-realistic, cgi, 3d, render, sketch, cartoon, drawing, not clear, noised" --prompt-strength 10 --steps 10 --model RV-5.1
RESULT OF FIRST RPOMPT:

SECOND PROPMT:
imagine --init-image T18.jpg --mask-prompt "shoes AND NOT (white surrounding){+5}" --mask-mode keep "commercial photography, a pair of shoes, black background, very detailed, high resolution, highly detailed, high quality" --negative-prompt "unreal, unrealistic, ugly, bad quality, not real, deformed iris, deformed pupils, semi-realistic, cgi, 3d, render, sketch, cartoon, drawing, not clear, noised" --prompt-strength 10 --steps 10 --model RV-5.1
RESULT OF SECOND PROMPT:

WITHOUT ANY MODIFICATION PROMPT
imagine --init-image T18.jpg --mask-prompt "shoes AND NOT (white surrounding)" --mask-mode keep "commercial photography, a pair of shoes, black background, very detailed, high resolution, highly detailed, high quality" --negative-prompt "unreal, unrealistic, ugly, bad quality, not real, deformed iris, deformed pupils, semi-realistic, cgi, 3d, render, sketch, cartoon, drawing, not clear, noised" --prompt-strength 10 --steps 10 --model RV-5.1
RESULT OF WITHOUT ANY MODIFICATION:

INITIAL IMAGE: